Lightning strike protection material assemblies, lightning strike protection material systems, and methods of use thereof

Abstract

The disclosure relates to lightning strike protection material assemblies, lightning strike protection material systems, and methods of using the same. A lightning strike protection material assembly includes a lightning strike expansion metal foil layer having a lightning strike expansion metal foil, and includes a resin impregnated gridding cloth layer having a non-metal gridding cloth impregnated with an impregnating resin having a customized viscosity and a customized cure profile. A lightning strike protection material assembly is configured for laying on and co-curing with an uncured composite laminate assembly, the composite laminate assembly having a plurality of structural ply layers pre-impregnated with a structural resin. The structural resin has a structural resin viscosity and a structural resin cure profile that differ from the tailored viscosity and the tailored cure profile to prevent mixing of the structural resin and the impregnating resin during co-curing to allow the impregnating resin to effectively encapsulate the lightning expansion metal foil and provide a defined resin boundary. And forming a cured lightning protection composite material structure.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to lightning strike protection material assemblies, systems, and methods, and in particular to lightning strike protection material assemblies, systems, and methods for composite structures, such as aircraft composite structures. BACKGROUND

[0002] Lightning strike protection material systems and methods have been developed to provide lightning strike protection functionality for composite structures, such as aircraft composite structures, rotorcraft composite structures, spacecraft composite structures, and other aerospace vehicle composite structures. Several known lightning strike protection material systems and methods incorporate metal foil systems of various configurations into composite outer air surfaces of an aircraft, such as skin panels on wings, horizontal stabilizers, and fuselages, to provide improved electrical conductivity and distribute and divert electrical current away from flight critical areas and underlying aircraft components, thereby minimizing physical damage from lightning strike events.

[0003] Known lightning strike protection material systems and methods can include lightning strike protection materials made from expanded metal foils with resins that have similar cure profiles and viscosities to the structural resins in the composite structures underneath the lightning strike protection materials. Due to the similar cure profiles and viscosities, during curing, the resins of the lightning strike protection materials mix with the structural resins, creating areas where two different materials exist in close proximity, and resulting in less resin to encapsulate and protect the expanded metal foils. As a result, in operating environments, during repeated cyclic thermal and moisture exposure of the composite structures with lightning strike protection materials, due to differences in coefficient of thermal expansion (CTE) and coefficient of moisture expansion (CME) between the lightning strike protection materials and the underlying composite structures, and because the lightning strike protection materials generally have a higher CTE than the underlying composite structures, the lightning strike protection materials can expand faster than the underlying composite structures. This thermal and moisture exposure creates stresses and strains, and due to the large difference in CTE, can ultimately cause undesirable micro-cracking in the different lightning strike protection materials and the underlying composite structures. Such micro-cracks can form in the areas of the expanded metal foils and propagate through the mixed resin areas into the underlying composite structures. This, in turn, can result in increased costs for repairs or rework, and can compromise the lightning strike protection material systems.

[0004] Accordingly, there is a need in the art for an improved lightning strike protection material assembly, system, and method that prevents the lightning strike protection material's resin and the underlying composite structure's structural resin from mixing during cure or co-cure, avoids creating areas where the two different materials are in close proximity to each other, provides sufficient lightning strike protection material resin during cure or co-cure to effectively encapsulate the lightning strike protection material's expanded metal foil, minimizes or prevents micro-cracking and has increased resistance to micro-cracking, and prevents degradation into the underlying composite structure to avoid repair or rework, and provides advantages over known lightning strike protection material assemblies, systems, and methods. SUMMARY

[0005] Example implementations of the present disclosure provide an improved lightning strike protection material assembly, system, and method. As discussed in the following detailed description, versions of the improved lightning strike protection material assembly, system, and method can provide significant advantages over known assemblies, systems, and methods.

[0006] In one version of the present disclosure, a lightning strike protection material assembly is provided. The lightning strike protection material assembly includes a lightning strike expanded metal foil layer including a lightning strike expanded metal foil. The lightning strike protection material assembly also includes a resin-impregnated scrim layer laminated to the lightning strike expanded metal foil layer. The resin-impregnated scrim layer includes a non-metallic scrim impregnated with an impregnation resin. The impregnation resin has a custom viscosity and a custom cure profile.

[0007] The lightning strike protection material assembly is configured for laying up on and co-curing with an uncured composite laminate assembly composed of a plurality of structural ply layers pre-impregnated with a structural resin. The structural resin has a structural resin viscosity and a structural resin cure profile that are different from the custom viscosity and the custom cure profile of the impregnation resin to prevent the structural resin and the impregnation resin from mixing during co-cure to allow the impregnation resin to effectively encapsulate the lightning strike expanded metal foil and provide defined resin boundaries. A cured lightning strike protection composite structure is formed from the co-cured lightning strike protection material assembly and the uncured composite laminate assembly. The cured lightning strike protection composite structure has lightning strike protection functionality and has increased resistance to micro-cracking and degradation resistance.

[0008] In another version of the present disclosure, a lightning strike protection material system is provided. The lightning strike protection material system includes a lightning strike protection material assembly. The lightning strike protection material assembly includes a lightning strike expanded metal foil layer including a lightning strike expanded metal foil.

[0009] The lightning strike protection material assembly also includes a resin-impregnated scrim layer laminated to the lightning strike expanded metal foil layer. The resin-impregnated scrim layer includes a non-metallic scrim impregnated with an impregnation resin. The impregnation resin has a custom viscosity and a custom cure profile.

[0010] The lightning strike protection material system further includes an uncured composite laminate assembly comprised of a plurality of structural ply layers pre-impregnated with a structural resin. The structural resin has a structural resin viscosity and a structural resin cure profile that are different from the custom viscosity and the custom cure profile of the impregnation resin.

[0011] The lightning strike protection material assembly is laid up on and co-cured with the uncured composite laminate assembly, and during co-curing, the structural resin and the impregnation resin do not mix and provide a defined resin boundary, and the impregnation resin effectively encapsulates the lightning strike expanding metal foil. The cured lightning strike protection composite structure is formed from the co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly. The cured lightning strike protection composite structure has lightning strike protection functionality, and has increased micro-cracking resistance and degradation resistance.

[0012] In another version of the disclosure, a method of using a lightning strike protection material system to provide increased micro-cracking resistance and degradation resistance to a cured lightning strike protection composite structure is provided. The method includes the step of providing a lightning strike protection material system.

[0013] The lightning strike protection material system includes a lightning strike protection material assembly. The lightning strike protection material assembly includes a lightning strike expanding metal foil layer including a lightning strike expanding metal foil. The lightning strike protection material assembly further includes a resin-impregnated scrim layer laminated to the lightning strike expanding metal foil layer. The resin-impregnated scrim layer includes a non-metallic scrim impregnated with an impregnation resin. The impregnation resin has a custom viscosity and a custom cure profile.

[0014] The lightning strike protection material system further includes an uncured composite laminate assembly. The uncured composite laminate assembly includes a plurality of structural ply layers pre-impregnated with a structural resin. The structural resin has a structural resin viscosity and a structural resin cure profile that are different from the custom viscosity and the custom cure profile of the impregnation resin.

[0015] The method further includes the step of laying up the lightning strike protection material assembly on the uncured composite laminate assembly.

[0016] The method further includes the step of co-curing the lightning strike protection material assembly on the uncured composite laminate assembly with heat in an autoclave. During co-curing, the structural resin and the impregnation resin do not mix and provide a defined resin boundary, and the impregnation resin effectively encapsulates the lightning strike expanding metal foil.

[0017] The method further includes the step of obtaining a cured lightning strike protection composite structure formed from the co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly, and using the lightning strike protection material system to provide increased micro-cracking resistance and degradation resistance to the cured lightning strike protection composite structure and lightning strike protection functionality.

[0018] The features, functions, and benefits discussed can be implemented in BRIEF DESCRIPTION OF DRAWINGS

[0019] The present disclosure can be better understood with reference to the following detailed description and drawings, in which:

[0020] FIG. 1A is an illustration of a block diagram of an exemplary lightning strike protection material assembly of the present disclosure;

[0021] FIG. 1B is an illustration of a block diagram of an exemplary lightning strike protection material system of the present disclosure;

[0022] FIG. 2A is an illustration of a front cross-sectional view of an exemplary lightning strike protection material assembly of the present disclosure;

[0023] FIG. 2B is an illustration of a front cross-sectional view of an exemplary lightning strike protection material system of the present disclosure showing the application of a lightning strike protection material to an uncured composite laminate assembly; FIG. 2A of the lightning strike protection material assembly of

[0024] FIG. 2C is an illustration of a front cross-sectional view of the lightning strike protection material system of FIG. 2B in an autoclave;

[0025] FIG. 2D is an illustration of a front cross-sectional view of an exemplary cured lightning strike protection composite material structure of the present disclosure;

[0026] FIG. 2E is an illustration of a front cross-sectional view of the cured lightning strike protection composite material structure of FIG. 2D showing micro-cracking;

[0027] FIG. 3A is an illustration of a graph showing viscosity versus temperature during curing for an exemplary lightning strike protection material system of the present disclosure;

[0028] FIG. 3B is an illustration of a graph showing viscosity versus temperature during curing for a prior art known resin system for lightning strike protection materials;

[0029] FIG. 4 is an illustration of a flow chart of an exemplary version of the method of the present disclosure;

[0030] FIG. 5is an illustration of a diagram of an aircraft incorporating an exemplary cured lightning strike protection composite material structure of the present disclosure;

[0031] FIG. 6 is an illustration of a flowchart of an exemplary aircraft manufacturing and maintenance method; and

[0032] FIG. 7 is an illustration of an exemplary block diagram of an aircraft.

[0033] The drawings illustrated in the present disclosure represent the present versions and will be discussed in detail only with regard to the differences. DETAILED DESCRIPTION

[0034] The disclosed versions will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, versions of the disclosed versions are shown. Indeed, a variety of versions can be provided as is readily apparent to the skilled artisan, and the disclosure will not be limited to the versions explicitly set forth herein. Rather, the versions are presented so as to enable a thorough and complete disclosure of the disclosure and to convey full scope of the disclosure to those skilled in the art.

[0035] The specification includes references to “one version” or “an version”. Instances of the phrase “one version” or “an version” do not necessarily refer to the same version. Particular features, structures, or characteristics can be combined in any suitable manner consistent with the disclosure. All features disclosed in the specification, including the claims, abstract, and drawings, can be combined in any combination, except combinations that would be inconsistent with the disclosure. Unless otherwise expressly stated, each feature disclosed in the specification (including the claims, abstract, and drawings) can be replaced with an alternative feature serving the same, equivalent, or similar purpose.

[0036] As used herein, “includes” is an open term and, as used in the claims, does not exclude additional structures or steps.

[0037] As used herein, “configured to” means that various parts or components can be described or claimed in a manner that is “configured to” perform one or more tasks. In this context, “configured to” is used in the sense of “designed to” or “adapted to” and is used in the sense of “designed to” or “adapted to” perform the task(s) in question. As such, the parts or components can be said to be configured to perform the task(s) even when the specified parts or components are not currently operational (e.g., are not on).

[0038] As used herein, the terms “first,” “second,” and the like, are used as labels for items that are described herein and do not necessarily describe a specific order or sequence.

[0039] As used herein, an element or step recited in the singular and preceded with the word "a" or "an" should be understood as not excluding plural elements or steps unless explicitly stated otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, the term "combination" is inclusive of combinations, subsets, and / or any and all permutations thereof.

[0040] As used herein, the phrase "at least one of" followed by a listing of two or more items means that any of the listed items can be utilized individually, or in any combination, and that one of the listed items can be utilized even if only one of the items is utilized. In other words, "at least one of" indicates that a selection of one or more of the listed items is possible, and that a selection of only one of the listed items is also possible.

[0041] Reference will now be made to FIG. 1A to FIG. 1B , FIG. 1A is a diagram of an example lightning strike protection material assembly 10 of the present disclosure, and FIG. 1B is a diagram of an example lightning strike protection material system 12 of the present disclosure including FIG. 1A the lightning strike protection material assembly 10 of FIG. 1A to FIG. 1B The boxes in the diagrams represent elements, and the lines connecting the various boxes do not imply any particular dependency of elements. Further, the connecting lines shown in the various diagrams contained herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements, but it should be noted that other alternative or additional functional relationships or physical connections can exist in versions disclosed herein. When implemented in the illustrative examples, one or more of these boxes can be combined, divided, or combined and divided into different boxes. Further, FIG. 1A the lightning strike protection material assembly 10 of FIG. 1B the lightning strike protection material system 12 of

[0042] FIG. 1A A lightning strike protection material assembly (LSPMA) 10 is shown, which is cured 14 (see FIG. 1B ) or co-cured 14a (see FIG. 1B) before, during, and after each of the stages of the curing 14 or co-curing 14a include an uncured lightning strike protection material assembly (LSPMA) 10a, a partially cured lightning strike protection material assembly (LSPMA) 10b, and / or a cured lightning strike protection material assembly (LSPMA) 10c. For example, the uncured lightning strike protection material assembly 10a is in an uncured stage before the curing 14 or co-curing 14a, the partially cured lightning strike protection material assembly 10b is in a partially cured stage during the curing 14 or co-curing 14a, and the cured lightning strike protection material assembly 10c is in a cured stage after or post the curing 14 or co-curing 14a, where co-curing causes the layers to be cured simultaneously. As FIG. 1A shown, the lightning strike protection material assembly 10 provides a lightning strike protection function 11.

[0043] Preferably, the lightning strike protection material assembly 10 undergoes co-curing 14a or curing 14 that is a rapid curing process 15 (see FIG. 1B , for example, disclosed in U.S. Patent No. 11,752,708 B2, which is hereby incorporated by reference in its entirety.

[0044] As FIG. 1A shown, in one exemplary version, the lightning strike protection material assembly 10 includes a lightning strike expansion metal foil layer 16. The lightning strike expansion metal foil layer 16 includes a lightning strike expansion metal foil 18 (see FIG. 1A ). The lightning strike expansion metal foil layer 16 has a first side 20 (see FIG. 2A , for example, a top side 20a (see FIG. 2A ); and a second side 22 (see FIG. 2A , for example, a bottom side 22a (see FIG. 2A ). The lightning strike expansion metal foil layer 16 also has a metal foil layer body 24 (see FIG. 2A ) disposed between the first side 20 and the second side 22, and disposed between end portions 25 (see FIG. 2A ) of the lightning strike expansion metal foil layer 16.

[0045] As FIG. 1A shown, the lightning strike expansion metal foil 18 includes a non-continuous (NON-CONT.) metal foil (MF) 26 that includes one or more of: a perforated metal foil (MF) 28, an expanded metal foil (MF) 29, a metal mesh 30, a metalized fiber mesh 31, a metal screen 32, a metalized fiber fabric 33, a woven metal 34, a wire mesh 35, a metal foam 36, an open cell metal foam 36a, or another suitable non-continuous metal foil 26.

[0046] As FIG. 1A shown, the lightning strike expansion metal foil 18 also includes a metal material 38 or a metal alloy material 40. AsFIG. 1A As further shown, the metallic material 38 includes one or more of the following: copper 38a, aluminum 38b, titanium 38c, nickel 38d, gold 38e, silver 38f, or another suitable metallic material 38. FIG. 1A As further shown, the metal alloy material 40 includes one or more of the following: copper alloy 40a, aluminum alloy 40b, titanium alloy 40c, nickel alloy 40d, gold alloy 40e, silver alloy 40f, bronze 40g, brass 40h, or another suitable metal alloy material 40.

[0047] like FIG. 1A As shown, in one exemplary version, the lightning protection material assembly 10 further includes a resin-impregnated mesh layer 42 laminated to the lightning-expanded metal foil layer 16. FIG. 1A As further shown, the resin-impregnated mesh layer 42 includes a non-metallic mesh 44 impregnated with impregnating resin (IR) 45, which is also known as lightning protection material resin 46.

[0048] like FIG. 1A As further shown, the non-metallic mesh fabric 44 includes one of the following: non-metallic mesh fabric pad 44a, glass fiber mesh fabric pad 44b, carbon fiber mesh fabric pad 44c, woven mesh fabric pad 44d, knitted polyester mesh fabric pad 44e, nonwoven mesh fabric pad 44f, or another suitable non-metallic mesh fabric 44. The non-metallic mesh fabric 44 may also include a mesh fabric or carrier having glass fiber or glass fiber reinforcement, or having carbon fiber or carbon fiber reinforcement, having nylon fiber or nylon fiber reinforcement, having polyester fiber or polyester fiber reinforcement, or having another suitable fiber reinforcement.

[0049] The resin-impregnated mesh layer 42 has: a first side 48 (see FIG. 2A For example, top side 48a (see FIG. 2A ); and the second side 50 (see FIG. 2A For example, bottom side 50a (see...) FIG. 2A The resin-impregnated mesh layer 42 also has a mesh layer body 52 (see...). FIG. 2A It is disposed between the first side 48 and the second side 50, and is disposed at the end 54 of the resin-impregnated mesh layer 42 (see...). FIG. 2A )between.

[0050] In some versions, the lightning strike protection material assembly 10 can further include one or more additional layers on top of the lightning strike expanding metal foil layer 16. For example, a thin composite prepreg layer (e.g., a surface film or another suitable layer) can be added to and applied on top of the lightning strike expanding metal foil layer 16 to serve as a protective or reinforcing layer on top of the lightning strike expanding metal foil layer 16 to protect the lightning strike expanding metal foil layer 16 during subsequent sanding, painting, polishing, or other post-processing procedures.

[0051] FIG. 1A The impregnated resin 45 is shown to include uncured impregnated resin (IR) 45a before curing 14 (see FIG. 1B ) or co-curing 14a (see FIG. 1B ), during curing 14 or co-curing 14a, and after or post-curing 14 or co-curing 14a. For example, the uncured impregnated resin 45a is in an uncured stage before curing 14 or co-curing 14a, the partially cured impregnated resin 45b is in a partially cured stage during curing 14 or co-curing 14a, and the cured impregnated resin 45c is in a cured stage after or post-curing 14 or co-curing 14a. When the impregnated resin 45 is initially heated with the curing 14 or co-curing 14a, the initial heating is sufficient to gel the impregnated resin 45 (e.g., the uncured impregnated resin 45a) into a gel 56 (see FIG. 1A ) as discussed in further detail below.

[0052] As shown in FIG. 1A , the impregnated resin 45 (e.g., the lightning strike protection material resin 46) includes a thermoset resin 58. As further shown in FIG. 1A , the thermoset resin 58 includes one or more of an adhesive 58a, an epoxy 58b, a phenolic 58c, a polyimide 58d, a bismaleimide 58e, a polyurethane 58f, a fluoropolymer 58g, a cyanate ester 58h, or another suitable thermoset resin 58. The impregnated resin 45 can further include an ultraviolet light resistant impregnated resin, an aliphatic epoxy impregnated resin, a fire retardant impregnated resin, or another suitable impregnated resin 45.

[0053] As shown in FIG. 1AAs shown, the impregnation resin 45 has a viscosity, such as a custom viscosity 60a, has a cure profile (CP) 62, such as a custom cure profile (CP) 62a, and has a rheology 64, such as a custom rheology 64a. As used herein, “custom viscosity” means a viscosity of a resin, such as an impregnation resin in a lightning strike protection material assembly, that is related to a lightning strike expanding metal foil and is controlled, adjusted, and selected to be different from a viscosity of a structural resin in a structural assembly, such as a composite laminate assembly, to prevent or minimize mixing of the impregnation resin and the structural resin during co-curing or curing.

[0054] As used herein, “custom cure profile” means a cure profile, such as optimized cure times and temperatures, of a resin, such as an impregnation resin in a lightning strike protection material assembly, that is controlled, adjusted, and selected to be different from a cure profile of a structural resin in a structural assembly, such as a composite laminate assembly, so that the impregnation resin can initiate cross-linking at lower temperatures to rapidly increase the viscosity of the impregnation resin to allow the impregnation resin to encapsulate the lightning strike expanding metal foil while maintaining separation and non-mixing of the impregnation resin and the structural resin.

[0055] As used herein, “custom rheology” means a rheological or flow behavior relationship between a viscosity of a material, such as gelling and hardening, for example, during curing, and a temperature of the material, such as a resin, including an impregnation resin in a lightning strike protection material assembly, during curing, that is controlled, adjusted, and selected to be different from a rheology of a structural resin in a structural assembly, such as a composite laminate assembly, to prevent or minimize mixing of the impregnation resin and the structural resin during co-curing or curing and to provide improved hot wet out anti-microcracking performance in a co-cured composite material structure, such as a co-cured composite laminate structure having a structural component and a lightning strike protection component.

[0056] The custom viscosity 60a, the custom cure profile 62a, and the custom rheology 64a of the impregnation resin 45 are related to the lightning strike expanding metal foil 18 and provide chemical compatibility 66 (see FIG. 1B ) and adhesive capability 68 (see FIG. 1B ) between the impregnation resin 45 and a structural resin 70 (see FIG. 1B ), such as a structural prepreg resin, of a structural assembly 71 (see FIG. 1A ) coupled or bonded to the lightning strike protection material assembly 10, such as a composite laminate assembly 72 (see FIG. 1A ).

[0057] The lightning strike protection material assembly 10 is configured for layup 73 (see FIG. 1B ) in a layup process 73a and is laid up on a structural assembly 71 (see FIG. 1B ), such as a composite laminate assembly 72 (seeFIG. 1B ), such as an uncured composite laminate assembly 72a, in one version, the structural assembly 71 includes a plurality of structural plies 74 (see FIG. 1B ), such as a plurality of structural ply layers 75 (see FIG. 1B ). Alternatively, the structural assembly 71, such as a composite laminate assembly 72, such as an uncured composite laminate assembly 72a, can be laid up on the lightning strike protection material assembly 10. As shown in FIG. 1B , the structural resin 70 has a structural resin viscosity 60b, a structural resin cure profile 62b, and a structural resin rheology 64b that are different from the custom viscosity 60a, the custom cure profile 62a, and the custom rheology 64a of the infused resin 45 to prevent the structural resin 70 and the infused resin 45 from mixing during the co-cure 14a or cure 14 and to allow the infused resin 45 to effectively encapsulate the lightning strike expanding metal foil 18 via the encapsulation 76 (see FIG. 1A ) and provide a defined resin boundary 78 (see FIG. 1B ). Further, the custom viscosity 60a of the infused resin 45 is greater than the structural resin viscosity 60b of the structural resin 70 to prevent the infused resin 45 and the structural resin 70 from mixing during the co-cure 14a or cure 14.

[0058] The custom cure profile 62a of the infused resin 45 initiates cross-linking at a lower temperature 114 (see FIG. 1B ) to rapidly increase the custom viscosity 60a of the infused resin 45 to allow the infused resin 45 to effectively encapsulate the lightning strike expanding metal foil 18 via the encapsulation 76 while maintaining separation and non-mixing of the infused resin 45 from the structural resin 70. Further, the initial custom viscosity 60c (see FIG. 1A ) of the infused resin 45 can be significantly different from the initial structural resin viscosity 60d (see FIG. 1B ) of the structural resin 70 to minimize mixing of the infused resin 45 and the structural resin 70 during the initial cure 14b (see FIG. 1B ) or the initial co-cure 14c (see FIG. 1B ). As used herein, “encapsulation” means hardening the infused resin (e.g., thermoset resin) around the lightning strike expanding metal foil to keep the lightning strike expanding metal foil separate from the structural resin and the composite laminate assembly or structure. For example, during the co-cure 14a, the infused resin 45 in the non-metallic scrim 44 is forced into the openings 130 (see FIG. 2C ) of the lightning strike expanding metal foil 18 such that the infused resin 45 completely encapsulates or completely surrounds the lightning strike expanding metal foil 18.

[0059] The tailored viscosity 60a, the tailored cure profile 62a, and the tailored rheology 64a of the impregnation resin 45 and the structural resin viscosity 60b, the structural resin cure profile 62b, and the structural resin rheology 64b of the structural resin 70 can be sufficiently and significantly different to ensure that the impregnation resin 45 sufficiently and effectively encapsulates the lightning strike expanding metal foil 18 to provide in-service protection. The impregnation resin 45 has properties that are compatible with the structural resin 70 that are related to thermal and moisture cycling and prevent or minimize resin mixing of the impregnation resin 45 and the structural resin 70 during the curing 14 or co-curing 14a.

[0060] The cured lightning strike protection (LSP) composite structure 80 (see FIG. 1B ), such as the co-cured lightning strike protection (LSP) composite structure 80a (see FIG. 1B ), is formed from the curing 14 or co-curing 14a of the lightning strike protection material assembly 10, such as the uncured lightning strike protection material assembly 10a, and a structural assembly 71 (see FIG. 1B ), such as the composite laminate assembly 72 (see FIG. 1B ), such as the uncured composite laminate assembly 72a (see FIG. 1B ). The cured lightning strike protection composite structure 80, such as the co-cured lightning strike protection composite structure 80a, is comprised of the cured lightning strike protection material assembly 10c (see FIG. 1B ) coupled or bonded to the cured composite laminate assembly 72c (see FIG. 1A ). The cured lightning strike protection material assembly 10c provides the lightning strike protection function 11 (see FIG. 1A ) to the underlying cured composite laminate assembly 72c. Thus, the cured lightning strike protection composite structure 80 has the lightning strike protection function 11. In addition, the cured lightning strike protection composite structure 80 has increased microcracking resistance 82 (see FIG. 1B ) and degradation resistance 84 (see FIG. 1B ).

[0061] The immiscibility of the impregnation resin 45 and the structural resin 70 reduces any damage to the impregnation resin 45 and the structural resin 70 caused by the difference in the coefficient of thermal expansion (CTE) 86a (see FIG. 1A ) of the lightning strike expanding metal foil 18 (see FIG. 1A ) and the coefficient of thermal expansion (CTE) 86b (see FIG. 1B ) of the composite laminate assembly 72 (see FIG. 1B ). In addition, the immiscibility of the impregnation resin 45 and the structural resin 70 reduces any damage to the impregnation resin 45 and the structural resin 70 caused by the difference in the coefficient of moisture expansion (CME) 88a (see FIG. 1A ) of the lightning strike expanding metal foil 18 and the coefficient of moisture expansion (CME) 88b (see FIG. 1BThe differences in the CTE 86a of the lightning-expanded metal foil 18 and the CTE 86b of the composite laminate assembly 72 during thermal and moisture cycling events can cause any damage to the impregnating resin 45 and the structural resin 70. Typically, during thermal and moisture cycling events, the metal expands more than the composite material, for example, in the temperature range of -70℉ (minus 70 degrees Fahrenheit) to 160℉ (160 degrees Fahrenheit), and there is a possibility of cracking or microcracking. The lightning protection material assembly 10 and lightning protection material system 12 disclosed herein mitigate the difference in CTE 86a between the lightning-expanded metal foil 18 and the composite laminate assembly 72 during thermal and moisture cycling events to mitigate or prevent microcracking or cracking, and provide increased resistance to microcracking 82 in the cured lightning protection composite material structure 80.

[0062] Furthermore, the cured lightning protection composite structure 80 exhibits significantly lower surface porosity and improved performance during thermal and humid cycling events, achieved through a minimal or reduced number of microcracks 83 in the lightning protection composite structure 80 cured after exposure to thermal and humid cycling (see [link]). FIG. 2E This is achieved through cracks or fissures. Furthermore, the cured lightning protection composite structure 80 has deterioration resistance 84 to prevent deterioration (e.g., microcracks or cracks) from extending into the structural component 71 (e.g., cured composite laminate component 72c) and the multiple structural laminations 75. Any microcracks 83 that may occur (see [reference]). FIG. 2E The cracks are contained within the cured lightning protection material component 10c and do not extend into the structural component 71, such as the cured composite laminate component 72c.

[0063] As used herein, “thermal-moisture cycling” or “thermal-moisture cycling event” refers to the process by which a material is exposed to changes in heat and / or moisture during its service life, such as absorbing heat and moisture, for example, the movement of an aircraft back and forth between a parking position on the ground at ambient or high temperatures and a flight phase in the air at cold or freezing temperatures.

[0064] FIG. 1B A lightning protection material system (LSPMS) 12 is shown, which includes, at various stages before, during, and after curing 14 or co-curing 14a, an uncured lightning protection material system (LSPMS) 12a, a partially cured lightning protection material system (LSPMS) 12b, and / or a cured lightning protection material system (LSPMS) 12c. For example, the uncured lightning protection material system 12a is in an uncured stage before curing 14 or co-curing 14a, the partially cured lightning protection material system 12b is in a partially cured stage during curing 14 or co-curing 14a, and the cured lightning protection material system 12c is in a cured stage after curing 14 or co-curing 14a.

[0065] like FIG. 1BAs shown, the lightning strike protection material system 12 includes the lightning strike protection material assembly 10 described above with respect to FIG. 1A the lightning strike protection material assembly 10 discussed in detail above. The lightning strike protection material assembly 10 includes a lightning strike intumescent metal foil layer 16 (see FIG. 1A ), which includes a lightning strike intumescent metal foil 18 (see FIG. 1A ). As shown in FIG. 1A and described above, the lightning strike intumescent metal foil 18 includes a non-continuous metal foil 26, which includes one or more of a perforated metal foil (MF) 28, an intumescent metal foil (MF) 29, a metal mesh 30, a metalized fiber mesh 31, a metal screen 32, a metalized fiber fabric 33, a woven metal 34, a wire mesh 35, a metal foam 36, an open cell metal foam 36a, or another suitable non-continuous metal foil 26. As further shown in FIG. 1A and described above, the lightning strike intumescent metal foil 18 includes a metal material 38 or a metal alloy material 40, wherein the metal material 38 includes one or more of copper 38a, aluminum 38b, titanium 38c, nickel 38d, gold 38e, silver 38f, or another suitable metal material 38, and the metal alloy material 40 includes one or more of a copper alloy 40a, an aluminum alloy 40b, a titanium alloy 40c, a nickel alloy 40d, a gold alloy 40e, a silver alloy 40f, a bronze 40g, a brass 40h, or another suitable metal alloy material 40.

[0066] As described above, the lightning strike protection material assembly 10 also includes a resin-impregnated scrim layer 42 (see FIG. 1A ) laminated to the lightning strike intumescent metal foil layer 16. The resin-impregnated scrim layer 42 includes a non-metallic scrim 44 (see FIG. 1A ) impregnated with an impregnation resin 45 (see FIG. 1A ), which is also referred to as a lightning strike protection material resin 46 (see FIG. 1A ). As further shown in FIG. 1A , the non-metallic scrim 44 includes one of a non-metallic scrim mat 44a, a fiberglass scrim mat 44b, a carbon fiber scrim mat 44c, a woven scrim mat 44d, a knitted polyester scrim mat 44e, a non-woven scrim mat 44f, or another suitable non-metallic scrim 44. As further shown in FIG. 1A , the impregnation resin 45 includes a thermoset resin 58, which includes one or more of a mastic 58a, an epoxy 58b, a phenolic 58c, a polyimide 58d, a bismaleimide 58e, a polyurethane 58f, a fluoropolymer 58g, a cyanate ester 58h, or another suitable thermoset resin 58. As further shown in FIG. 1B , the impregnation resin 45 has a customized viscosity 60a, a customized cure profile 62a, and a customized rheology 64a.

[0067] like FIG. 1B As shown, the lightning protection material system 12 also includes structural components 71, such as a composite laminate component 72. For example... FIG. 1B As further shown, the composite laminate assembly 72 has a coefficient of thermal expansion (CTE) of 86b and a coefficient of moisture expansion (CME) of 88b. FIG. 1B As further shown, the composite laminate assembly (CLA) 72 includes an uncured composite laminate assembly (CLA) 72a, a partially cured composite laminate assembly (CLA) 72b, or a cured composite laminate assembly (CLA) 72c, and may be in the above-described form. The uncured composite laminate assembly 72a, the partially cured composite laminate assembly 72b, and / or the cured composite laminate assembly 72c exist at various stages before, during, and after curing 14a or co-curing 14a. For example, the uncured composite laminate assembly 72a is in an uncured stage before curing 14a or co-curing 14a, the partially cured composite laminate assembly 72b is in a partially cured stage during curing 14a or co-curing 14a, and the cured composite laminate assembly 72c is in a cured stage after curing 14a or co-curing 14a.

[0068] Structural component 71, such as composite laminate component 72 (e.g., in the form of uncured composite laminate component 72a, partially cured composite laminate component 72b, and cured composite laminate component 72c), includes a plurality of structural layers 74 pre-impregnated with structural resin 70 (e.g., structural prepreg resin) (see [link to documentation]). FIG. 1B ), for example, multiple structural layers 75 (see FIG. 1B Each structural sheet 75 includes sheet 75a (see...). FIG. 1B ), and the multiple structural sheet layers 75 include multiple sheets 75a.

[0069] Multiple structural sheets 75 and multiple sheets 75a each include structural fibers 91 (e.g., composite fibers 92 (see...) FIG. 1B Composite material (COMP.MAT.) 90 (see) FIG. 1B ).like FIG. 1BAs shown, the composite material 90 can include one or more of: one or more carbon fiber reinforced polymers (CFRP) 94 or carbon fiber reinforced plastics having carbon fibers 95; one or more glass fiber reinforced polymers (GFRP) 96 or glass fiber reinforced plastics having glass fibers 98 or glass filament fibers; one or more aramid polymers 100 or aramid plastics having aramid fibers 102, where "aramid" means aramid; or another suitable composite material 90 having structural fibers 91 (e.g., composite fibers 92).

[0070] The composite material 90 includes a matrix of structural resin 70 (see FIG. 1B ) reinforced with composite fibers 92. Each structural layer 74 (e.g., structural ply layer 75) can include a plurality of structural fibers 91 (e.g., composite fibers 92) that can be at least partially or even entirely encapsulated within the structural resin 70, uncured structural resin (SR) 70a (see FIG. 1B ), partially cured structural resin (SR) 70b (see FIG. 1B ), and / or cured structural resin (SR) 70c (see FIG. 1B ). Examples of the plurality of structural fibers 91 (e.g., composite fibers 92) include a plurality of carbon fibers 95, a plurality of glass fibers 98 or glass filament fibers, and / or a plurality of aramid fibers 102 or other suitable structural fibers 91. In a preferred example, the structural layer 74 and / or the structural fibers 91 (e.g., composite fibers 92) are included in and / or disposed in a plurality of structural ply layers 75 having layered plies 75a of the composite material 90 that includes the structural resin 70, e.g., in the form of uncured structural resin 70a, partially cured structural resin 70b, and / or cured structural resin 70c.

[0071] The plurality of structural layers 74 can include a plurality of structural ply layers 75 made of the composite material 90 that includes the structural resin 70, e.g., uncured structural resin 70a. Each of the plurality of structural layers 74 (e.g., the plurality of structural ply layers 75) can include a plurality of structural fibers 91 (e.g., a plurality of composite fibers 92) at least partially encapsulated within the structural resin 70 (e.g., uncured structural resin 70a). Each of the plurality of structural layers 74 (e.g., the plurality of structural ply layers 75) can include a plurality of carbon fibers 95 at least partially encapsulated within the structural resin 70 (e.g., uncured structural resin 70a).

[0072] As FIG. 1BAs shown, in one version, the structural resin (SR) 70 preferably includes a thermoset structural resin (SR) 104 that includes one or more of an epoxy structural resin (SR) 104a, a phenolic structural resin (SR) 104b, a polyimide structural resin (SR) 104c, a bismaleimide structural resin (SR) 104d (e.g., a polybismaleimide structural resin), a polyurethane structural resin (SR) 104e, a fluoropolymer structural resin (SR) 104f, a cyanate ester structural resin (SR) 104g, or another suitable thermoset structural resin 104. In other versions, the structural resin 70 can include and / or be any suitable resin that can have, define, and / or exhibit a structural resin viscosity 60b (see FIG. 1B ) (e.g., an initial structural resin viscosity 60d (see FIG. 1B )), a structural resin cure profile 62b (see FIG. 1B ), a structural resin rheology 64b (see FIG. 1B ), a structural resin gel point temperature, and / or a structural resin gel time.

[0073] As further shown in FIG. 1A , the structural resin 70 has a structural resin viscosity 60b (e.g., an initial structural resin viscosity 60d), a structural resin cure profile 62b, and a structural resin rheology 64b that are different from the tailored viscosity 60a, the tailored cure profile 62a, and the tailored rheology 64a of the impregnation resin 45 to prevent the structural resin 70 and the impregnation resin 45 from mixing during co-cure 14a (see FIG. 2D ) or cure 14 (see FIG. 2C ) and to allow the impregnation resin 45 to effectively encapsulate the lightning strike expanding metal foil 18 via the encapsulation 76 (see FIG. 2D ) and provide a defined resin boundary 78 (see FIG. 1B ). This is different from known resin systems in which mixing of the resin (e.g., a scrim resin) and the structural laminate resin occurs during co-cure or cure such that no defined or distinct resin boundary is formed.

[0074] As shown in FIG. 2D , the lightning strike protection material assembly 10 (e.g., an uncured lightning strike protection material assembly 10a (see FIG. 2C )) is laid up via a layup process 73a on the composite laminate assembly 72 (e.g., an uncured composite laminate assembly 72a) to form a layup assembly (1A) 106. As FIG. 2DAs shown, depending on the stage of co-curing 14a or curing 14, e.g., prior to co-curing 14a, during co-curing 14a, or after co-curing 14a or post, the laminated assembly (LA) 106 can be in the form of an uncured laminated assembly (LA) 106a, a partially cured laminated assembly (LA) 106b, and / or a cured laminated assembly (LA) 106c.

[0075] The laminated assembly 106 (see FIG. 1A ), e.g., the uncured laminated assembly 106a including the uncured lightning strike protection material assembly 10a laid up on and coupled to the uncured composite laminate assembly 72a, is placed in a heating apparatus (see FIG. 2D ), e.g., an autoclave 110 (see FIG. 1B ) or another suitable heating apparatus 108, to undergo co-curing 14a (see FIG. 1B ) or curing 14 (see FIG. 1A ). Preferably, the uncured laminated assembly 106a including the uncured lightning strike protection material assembly 10a laid up on and coupled to the uncured composite laminate assembly 72a undergoes a rapid curing process 15 (see FIG. 1B ), e.g., as disclosed in U.S. Patent No. 11,752,708 B2, which is hereby incorporated by reference in its entirety.

[0076] During co-curing 14a in the heating apparatus 108, e.g., the autoclave 110, the laminated assembly 106, e.g., the uncured laminated assembly 106a, is heated (e.g., initial heating) at a temperature (TEMP.) 114, e.g., an initial temperature (TEMP.) 114a (see FIG. 5 ), with heat 112 (see FIG. 5 ), e.g., an initial heat 112a (see FIG. 5 ), to generate a partially cured laminated assembly 106b (see FIG. 1B ), the uncured laminated assembly 106a including the uncured lightning strike protection material assembly 10a laid up on and coupled to the uncured composite laminate assembly 72a, the partially cured laminated assembly 106b including a partially cured lightning strike protection material assembly 10b (see FIG. 2E ) laid up on and coupled to a partially cured composite laminate assembly 72b (see FIG. 2E ). The partially cured lightning strike protection material assembly 10b (see FIG. 2A). The initial heat 112a and the initial temperature 114a of the initial heating are preferably at least 90 °C (ninety degrees Celsius, 194 degrees Fahrenheit (°F)) and at most 140 °C (one hundred forty degrees Celsius, 284 degrees Fahrenheit (°F)). The initial heating includes a heating time 116 (see FIG. 2A ) of at least 2 (two) minutes and at most 30 (thirty) minutes, for example, an initial heating time 116a (see FIG. 1B ). The initial heating with the initial heat 112a is sufficient to gelatinize the uncured infusion resin 45 into a gel 56 (see FIG. 1B ), but the initial heating with the initial heat 112a is insufficient to gelatinize the uncured structural resin 70.

[0077] During the co-curing 14a in the heating apparatus 108 (e.g., autoclave 110), the partially cured laminate assembly 106b (see FIG. 2A ) is subsequently heated (e.g., subsequent heating) with a subsequent heat 112b (see FIG. 2A ) at a desired subsequent temperature (TEMP.) 114b (see ) until it reaches a final heat 112c and reaches a final temperature (TEMP.) 114c that is greater than the initial temperature 114a to generate a cured laminate assembly 106c (see

[0078] ), the partially cured laminate assembly 106b including the partially cured lightning strike protection material assembly 10b laid up on and coupled to the partially cured composite laminate assembly 72b, the cured laminate assembly 106c including the cured lightning strike protection material assembly 10c laid up on and coupled to the cured composite laminate assembly 72c. The combination of the initial heating, the subsequent heating, and the final heating is sufficient to cure (e.g., fully cure) both the infusion resin 45 and the structural resin 70. FIG. 1A The subsequent heating with the subsequent heat 112b includes a subsequent heating time 116b (see

[0079] ) of at least 15 (fifteen) minutes and at most 120 (one hundred twenty) minutes. The final heat 112c and the final temperature 114c (e.g., final cure temperature) of the final heating is preferably at least 120 °C (one hundred twenty degrees Celsius, 248 degrees Fahrenheit (°F)) and at most 260 °C (two hundred sixty degrees Celsius, 500 degrees Fahrenheit (°F)). The difference between the final temperature 114c (e.g., final cure temperature) and the initial temperature 114a is at least 20 °C (twenty degrees Celsius, 68 degrees Fahrenheit (°F)). The initial heating includes the initial heating for the initial heating time 116a, wherein the subsequent heating includes the heating for the subsequent heating time 116b, and further wherein the difference between the subsequent heating time 116b and the initial heating time 116a is at least 10 (ten) minutes.

[0079] Co-curing 14a the stack assembly 106 (the stack assembly 106 includes the uncured lightning strike protection material assembly 10a laid up on and coupled to the uncured composite laminate assembly 72a) in the heating apparatus 108 (e.g., autoclave 110) with heat 112 can also include applying pressure 118 (see FIG. 2A ) to at least one of: the uncured composite laminate assembly 72a during initial heating under initial heat 112a; or the partially cured composite laminate assembly 72b during subsequent heating under subsequent heat 112b. In some examples, applying pressure 118 includes applying elevated atmospheric (ATM.) pressure 118a to the uncured composite laminate assembly 72a and / or the partially cured composite laminate assembly 72b from 0 to 150 psi (zero to one hundred fifty pounds per square inch) (0 atm (atmospheres) to 10.2 atm (atmospheres)). In some examples, applying pressure 118 includes utilizing the heating apparatus 108 (e.g., autoclave 110) to treat the uncured composite laminate assembly 72a with high pressure steam during initial heating and / or to treat the partially cured composite laminate assembly 72b with high pressure steam during subsequent heating.

[0080] During co-curing 14a, the structural resin 70 and the impregnation resin 45 do not mix and provide a defined resin boundary 78 (see FIG. 2A ) between the resin-impregnated grid cloth layer 42 (see FIG. 2A ) of the lightning strike protection material assembly 10 and the top structural plies layer 75b (see FIG. 1A 、 FIG. 2A ) of the composite laminate assembly 72 including the top plies 75c (see FIG. 1A 、 FIG. 2A ), for example, in the form of the partially cured laminate assembly 72b (see FIG. 2A ) and the cured composite laminate assembly 72c (see FIG. 2B ). The impregnation resin 45 effectively encapsulates the lightning strike expansion metal foil layer 16 (see FIG. 2B 、 FIG. 1B ).

[0081] As shown in FIG. 1B , after co-curing 14a or curing 14 is complete or finished, for example, after the rapid curing process 15 is complete, the cured lightning strike protection composite structure 80, for example, the co-cured lightning strike protection composite structure 80a, is obtained. The cured lightning strike protection composite structure 80 (e.g., the co-cured lightning strike protection composite structure 80a) includes the cured stack assembly 106c (see FIG. 2A), the cured stacked assembly 106c includes a cured lightning strike protection material assembly 10c (see FIG. 2B ) co-cured with the structural assembly 71 (e.g., cured composite laminate assembly 72c).

[0082] As shown in FIG. 2B , the cured lightning strike protection composite material structure 80 (e.g., co-cured lightning strike protection composite material structure 80a) can include or be part of a composite material (COMP.) structure (STRUC.) (CS) 120 (e.g., aircraft composite material structure (CS) 120a) in the form of a panel 122, such as a wing panel 122a of a wing 204 of an aircraft 200a (see FIG. 2B ), or a horizontal (HORIZ.) stabilizer (STABIL.) panel 122b of a horizontal (HORIZ.) stabilizer (STABIL.) 212 of an aircraft 200a (see FIG. 2B ), or a fuselage panel 122c of a fuselage 202 of an aircraft 200a (see FIG. 2B ). The cured lightning strike protection composite material structure 80 (e.g., co-cured lightning strike protection composite material structure 80a) can include or be part of another suitable composite material structure 120 or another suitable aircraft composite material structure 120a.

[0083] As shown in FIG. 2B , the cured lightning strike protection composite material structure 80 (e.g., co-cured lightning strike protection composite material structure 80a) has a lightning strike protection function (LSP) 11, and has increased micro-cracking resistance 82 and degradation prevention 84.

[0084] As described above, the cured lightning strike protection composite material structure 80 (e.g., co-cured lightning strike protection composite material structure 80a) has significantly less surface porosity after exposure to a thermal humidity cycle and improved performance in thermal humidity cycle events by having a minimum or reduced number of micro-cracks 83 (see FIG. 2B ) or cracks in the cured lightning strike protection composite material structure 80 (e.g., co-cured lightning strike protection composite material structure 80a). In addition, the cured lightning strike protection composite material structure 80 (e.g., co-cured lightning strike protection composite material structure 80a) has degradation prevention 84 to prevent degradation (e.g., micro-cracks or cracks) from extending into the structural assembly 71 (e.g., cured composite laminate assembly 72c) and the plurality of structural ply layers 75. Any micro-cracks 83 (see FIG. 2B) or the crack is contained in the cured lightning strike protection material assembly 10c and does not extend into the structural assembly 71 (e.g., cured composite laminate assembly 72c).

[0085] Reference is now made to FIG. 2B , FIG. 1B is a front cross-sectional view of an exemplary lightning strike protection material assembly 10 of the present disclosure (e.g., uncured lightning strike protection material assembly 10a) prior to co-curing 14a (see FIG. 2B ) or curing 14 (see FIG. 1B ) (e.g., using a rapid curing process 15 (see FIG. 2C ). As shown in FIG. 2C , the lightning strike protection material assembly 10 (e.g., uncured lightning strike protection material assembly 10a) includes a lightning strike expanding metal foil layer 16 comprised of a lightning strike expanding metal foil 18. As further shown in FIG. 2B , the lightning strike expanding metal foil layer 16 has a first side 20, e.g., a top side 20a, a second side 22, e.g., a bottom side 22a, and a metal foil layer body 24 disposed between the first side 20 and the second side 22 and between end portions 25 of the lightning strike expanding metal foil layer 16.

[0086] As further shown in FIG. 2C , in one version, the lightning strike protection material assembly 10 (e.g., uncured lightning strike protection material assembly 10a) includes a non-continuous metal foil 26 that includes a perforated metal foil 28. In other versions, as shown in FIG. 2C , the non-continuous metal foil 26 includes an expanding metal foil 29, a metal mesh 30, a metalized fiber mesh 31, a metal screen 32, a metalized fiber fabric 33, a woven metal 34, a wire mesh 35, a metal foam 36, an open cell metal foam 36a, or another suitable non-continuous metal foil 26.

[0087] As further shown in FIG. 2C , the lightning strike protection material assembly 10 (e.g., uncured lightning strike protection material assembly 10a) includes a resin-impregnated scrim layer 42 laminated to the lightning strike expanding metal foil layer 16. As further shown in FIG. 2C , the resin-impregnated scrim layer 42 includes a non-metallic scrim 44 impregnated with an impregnation resin 45.

[0088] As shown in FIG. 2C , in one version, the non-metallic scrim 44 includes a non-metallic scrim mat 44a. In other versions, as shown in FIG. 2C , the non-metallic scrim 44 includes a glass fiber scrim mat 44b, a carbon fiber scrim mat 44c, a woven scrim mat 44d, a knitted polyester scrim mat 44e, a non-woven scrim mat 44f, or another suitable non-metallic scrim 44.

[0089] like FIG. 1B As further shown, in one version, the impregnating resin 45 includes uncured impregnating resin 45a, which includes a thermosetting resin 58, such as adhesive 58a. In other versions, such as FIG. 1A As shown, the thermosetting resin 58 includes epoxy resin 58b, phenolic resin 58c, polyimide 58d, bismaleimide 58e, polyurethane 58f, fluoropolymer 58g, cyanate ester 58h, or another suitable thermosetting resin 58.

[0090] like FIG. 1B As further shown, the resin-impregnated mesh fabric layer 42 has: a first side 48, such as a top side 48a; a second side 50, such as a bottom side 50a; and a mesh fabric layer body 52 disposed between the first side 48 and the second side 50 and between the ends 54 of the resin-impregnated mesh fabric layer 42. FIG. 1B As further shown, the second side 22 (e.g., bottom side 22a) of the lightning-expanded metal foil layer 16 is directly applied to the first side 48 (e.g., top side 48a) of the resin-impregnated mesh layer 42, connecting to the first side 48 and in continuous contact with the first side 48.

[0091] Now for reference FIG. 1A , FIG. 1A This is an illustration of a front cross-sectional view of an exemplary lightning protection material system 12 of this disclosure (e.g., an uncured lightning protection material system 12a), showing the co-cured state 14a (see [link to documentation]). FIG. 1A ) or cure for 14 (see FIG. 2C )Before FIG. 2D A lightning protection material component 10 (e.g., an uncured lightning protection material component 10a) is laid on and applied to a structural component 71 (e.g., a composite laminate component 72 (e.g., an uncured composite laminate component 72a)) to form a laminate component 106 (e.g., an uncured composite laminate component 106a).

[0092] like FIG. 2D As shown, the lightning protection material assembly 10 (e.g., an uncured lightning protection material assembly 10a) includes a lightning-expanded metal foil layer 16 made of lightning-expanded metal foil 18, and further includes a resin-impregnated mesh layer 42 laminated to the lightning-expanded metal foil layer 16. FIG. 2D As shown, the resin-impregnated mesh layer 42 includes a non-metallic mesh 44, such as a non-metallic mesh pad 44a, which is impregnated with an impregnating resin 45, such as an uncured impregnating resin 45a, such as a thermosetting resin 58 in the form of an adhesive 58a. FIG. 2D The first side 20 (e.g., top side 20a) of the lightning-expanded metal foil layer 16 and the second side 50 (e.g., bottom side 50a) of the resin-impregnated mesh layer 42 are also shown.

[0093] FIG. 2C Also shown is a structural component 71 (e.g., a composite laminate component 72, such as an uncured composite laminate component 72a), having a plurality of structural layers 74, such as a plurality of structural layer sheets 75, each structural layer sheet 75 pre-impregnated with a structural resin 70, such as an uncured structural resin 70a. In one version, as FIG. 2C As shown, structural component 71 (e.g., composite laminate component 72) has four (4) structural layers 74, such as four (4) structural sheet layers 75, wherein each structural sheet layer 75 includes a sheet 75a, and multiple structural sheet layers 75 include multiple sheets 75a. In other versions, structural component 71 (e.g., composite laminate component 72) may have fewer than four (4) or more than four (4) structural layers 74 (e.g., structural sheet layers 75). FIG. 2D The top structural sheet layer 75b, consisting of a top sheet 75c, is shown. FIG. 2D A bottom layer 75d and an intermediate layer 75e stacked between the bottom layer 75d and the top layer 75c are also shown. FIG. 2D As shown, each of the top sheet 75c, the bottom sheet 75d, and the middle sheet 75e has a first side 124 (e.g., top side 124a) and a second side 126 (e.g., bottom side 126a).

[0094] like FIG. 2D As shown, the second side 50 (e.g., bottom side 50a) of the resin-impregnated mesh layer 42 of the lightning protection material assembly 10 (e.g., uncured lightning protection material assembly 10a) is laid on the first side 124 (e.g., top side 124a) of the top layer 75c of the plurality of structural layers 75 of the structural assembly 71 (e.g., composite laminate assembly 72), applied directly to the first side 124, connected to the first side 124, and in continuous contact with the first side 124.

[0095] like FIG. 1B As further shown, both structural sheet 75 and sheet 75a comprise a composite material 90 having structural fibers 91 (e.g., composite fibers 92). FIG. 1B As shown, composite material 90 may include one or more of the following: one or more carbon fiber reinforced polymers 94 or carbon fiber reinforced plastics having carbon fibers 95; one or more glass fiber reinforced polymers 96 or glass fiber reinforced plastics having glass fibers 98 or glass filaments; one or more aromatic polyamide polymers 100 or aromatic polyamide plastics having aromatic polyamide fibers 102; or another suitable composite material 90 having structural fibers 91, such as composite fibers 92.

[0096] like FIG. 1BAs further shown, in one version, the structural resin 70 includes a thermoset structural resin 104, which includes an epoxy structural resin 104a. In other versions, as shown, the thermoset structural resin 104 includes a phenolic structural resin 104b, a polyimide structural resin 104c, a bismaleimide structural resin 104d (e.g., a polybismaleimide structural resin), a polyurethane structural resin 104e, a fluoropolymer structural resin 104f, a cyanate ester structural resin 104g, or another suitable thermoset structural resin 104. FIG. 1A

[0097] Reference is now made to FIG. 1B , FIG. 2E is a depiction of a front cross-sectional view of the lightning strike protection material system 12 in the form of a partially cured lightning strike protection material system 12b during co-curing 14a in the interior 128 of a heating apparatus 108 (e.g., an autoclave 110). FIG. 2E is shown, which includes the lightning strike protection material assembly 10 (e.g., in the form of a partially cured lightning strike protection material assembly 10b) laid up on and applied to the structural assembly 71 (e.g., a composite laminate assembly 72, e.g., in the form of a partially cured composite laminate assembly 72b) during co-curing 14a. FIG. 2D

[0098] FIG. 2E is shown, which includes the lightning strike protection metal foil layer 16 composed of the lightning strike expanded metal foil 18 of the lightning strike protection material assembly 10 (e.g., in the form of a partially cured lightning strike protection material assembly 10b). FIG. 1B is further shown, which includes the resin-impregnated scrim layer 42 composed of the non-metallic scrim 44 (e.g., a non-metallic scrim mat 44a) of the lightning strike protection material assembly 10 (e.g., in the form of a partially cured lightning strike protection material assembly 10b), the non-metallic scrim 44 being impregnated with the impregnation resin 45 (e.g., in the form of a partially cured impregnation resin 45b).

[0099] FIG. 2E is further shown, which has a plurality of structural layers 74, e.g., a plurality of structural ply layers 75, wherein each structural ply layer 75 is pre-impregnated with the structural resin 70 (e.g., in the form of a partially cured structural resin 70b).

[0100] During co-curing 14a, the impregnation resin 45 (e.g., in the form of a partially cured impregnation resin 45b) in the non-metallic scrim 44 is forced into the openings 130 (see FIG. 1B ​​such that the impregnated resin 45 completely encapsulates or completely surrounds the lightning strike expanding metal foil 18. The impregnated resin 45 effectively encapsulates the lightning strike expanding metal foil 18 via the encapsulation 76 (see FIG. 2E ) to minimize mixing of the impregnated resin 45 and the structural resin 70 during the initial cure 14b (see FIG. 2E ) and the co-cure 14a. The customized viscosity 60a (see FIG. 2E ) of the impregnated resin 45 can be significantly different from the structural resin viscosity 60b (see FIG. 2E ) of the structural resin 70, which prevents mixing of the impregnated resin 45 and the structural resin 70 during the initial cure 14b (see FIG. 2C ) and the co-cure 14a. The customized cure profile 62a (see FIG. 2E ) of the impregnated resin 45 initiates cross-linking at lower temperatures to rapidly increase the customized viscosity 60a, allowing it to effectively encapsulate the lightning strike expanding metal foil 18 while maintaining separation and non-mixing of the impregnated resin 45 from the structural resin 70 in the plurality of structural ply layers 75 in the composite laminate assembly 72. The impregnated resin 45 having the customized viscosity 60a and the customized cure profile 62a related to the lightning strike expanding metal foil 18 ensures chemical compatibility 66 (see FIG. 2E ) and adhesive capability 68 (see FIG. 3A ) with the structural resin 70.

[0101] FIG. 3A It is further shown that a defined resin boundary 78 is formed between the resin impregnated mesh layer 42 of the lightning strike protection material assembly 10 and the top structural ply layer 75b of the composite laminate assembly 72 including the top ply 75c. The defined resin boundary 78 helps to prevent or minimize mixing of the impregnated resin 45 and the structural resin 70 during the co-cure 14a.

[0102] Reference is now made to FIG. 1B , FIG. 1A is an illustration of a front cross-sectional view of an exemplary cured lightning strike protection composite structure 80 (e.g., co-cured lightning strike protection composite structure 80a) of the present disclosure. As shown in FIG. 1B , the cured lightning strike protection composite structure 80 (e.g., co-cured lightning strike protection composite structure 80a) includes a laminate assembly 106 (e.g., in the form of a cured laminate assembly 106c) including a lightning strike protection material assembly 10 (e.g., in the form of a cured lightning strike protection material assembly 10c) co-cured and adhered to a structural assembly 71 (e.g., a composite laminate assembly 72, e.g., in the form of a cured composite laminate assembly 72c). FIG. 3A It is shown that the lightning strike protection material system 12 (in the form of a cured lightning strike protection material system 12c) after or following the co-cure 14a (see FIG. 1B ).

[0103] As a result of co-curing 14a (see FIG. 1A ), the impregnated resin 45 (e.g., in the form of the cured impregnated resin 45c) completely encapsulates or completely surrounds the strike foil 18 of the strike foil layer 16 via the encapsulation 76 to obtain an encapsulated strike foil 18a, as shown in FIG. 1A FIG. 1A The impregnated resin 45 (e.g., in the form of the cured impregnated resin 45c) is in the opening 130 of the strike foil 18 and also in the resin-impregnated scrim layer 42, as shown in

[0104] FIG. 1B A defined resin boundary 78 is also shown between the second side 50 (e.g., the bottom side 50a) of the resin-impregnated scrim layer 42 of the strike shield material assembly 10 and the first side 124 (e.g., the top side 124a) of the top structural ply layer 75b including the top ply 75c of the composite laminate assembly 72 (e.g., the cured composite laminate assembly 72c). The defined resin boundary 78 is a distinct boundary between the resin-impregnated scrim layer 42 and the cured composite laminate assembly 72c. This is unlike known resin systems where the mixing of the resin (e.g., the scrim resin) and the structural laminate resin occurs during co-curing or curing such that no defined or distinct resin boundary is formed.

[0105] The composite laminate assembly 72 (e.g., the cured composite laminate assembly 72c) has a plurality of structural plies 74 (e.g., a plurality of structural ply layers 75) with structural resin 70 (e.g., in the form of the cured structural resin 70c), as shown in FIG. 1B

[0106] The cured strike shield composite material structure 80 (e.g., the co-cured strike shield composite material structure 80a) has a lightning strike protection function (LSP) 11 (see FIG. 1B ), and has increased microcracking resistance 82 (see FIG. 1B ) and degradation resistance 84 (see FIG. 3A ). The cured strike shield composite material structure 80 (e.g., the co-cured strike shield composite material structure 80a) with the strike shield material assembly 10 and the strike shield material system 12 disclosed herein mitigates the difference in the CTE 86a (see FIG. 3A ) of the strike foil 18 and the CTE 86b (see FIG. 3A ) of the composite laminate assembly 72 during a thermal-humidity cycling event to mitigate or prevent microcracking or cracking and provide increased microcracking resistance 82 in the cured strike shield composite material structure 80 (e.g., the co-cured strike shield composite material structure 80a).

[0107] ​​Now for reference FIG. 3A , FIG. 3A It is incorporated into the composite material structure 120 (e.g., panel 122). FIG. 3A An illustration of a front cross-sectional view of a cured lightning protection composite material structure 80 (e.g., a co-cured lightning protection composite material structure 80a), and showing a lightning-expanded metal foil layer 16 including a lightning-expanded metal foil 18 through a lightning protection material assembly 10 (e.g., in the form of a cured lightning protection material assembly 10c) and microcracks 83 formed through a resin-impregnated mesh layer 42.

[0108] like FIG. 3A As shown, a defined resin boundary 78 formed between the second side 50 (e.g., bottom side 50a) of the resin-impregnated mesh layer 42 of the lightning protection material assembly 10 and the first side 124 (e.g., top side 124a) of the top structural sheet layer 75b including the top sheet 75c of the composite laminate assembly 72 (e.g., cured composite laminate assembly 72c) prevents microcracks 83 from extending into the structural assembly 71 (e.g., composite laminate assembly 72, in the form of cured composite laminate assembly 72c). The defined resin boundary 78 acts as a barrier to prevent microcracks 83 from extending into the cured composite laminate assembly 72c. Therefore, the cured lightning protection composite material structure 80 (e.g., co-cured lightning protection composite material structure 80a) has resistance to degradation 84 (see [reference]). FIG. 3B This is to prevent degradation (e.g., microcracks 83 or cracks) from extending into structural component 71 (e.g., cured composite laminate component 72c) and multiple structural layer sheets 75. Any microcracks 83 that may occur (see [link to relevant documentation]). FIG. 3B The cracks are contained within the cured lightning protection material component 10c and do not extend into the structural component 71 (e.g., the cured composite laminate component 72c).

[0109] Furthermore, the cured lightning protection composite material structure 80 (e.g., the co-cured lightning protection composite material structure 80a) has increased resistance to microcracks 82 (see [reference]). FIG. 3B To mitigate, minimize, or prevent the formation of microcracks 83 in the cured lightning protection composite material structure 80 (e.g., co-cured lightning protection composite material structure 80a). FIG. 1A A microcrack 83 is shown. Microcrack 83 can be observed during thermal cycling, during temperature changes, during tensile loading, or during fatigue loading. As described above, the cured lightning protection composite structure 80 (e.g., the co-cured lightning protection composite structure 80a) exhibits significantly lower surface porosity and improved performance in thermal cycling events after exposure to thermal and humid cycling, which is achieved by minimizing or reducing the number of microcracks 83 in the cured lightning protection composite structure 80 (e.g., the co-cured lightning protection composite structure 80a) (see [link to documentation]).FIG. 1B ) or cracks achieve.

[0110] Known composite structures having known resin systems, in which mixing of the resin (e.g., a mesh resin) and the structural laminate resin occurs during co-curing or curing, can form a greater number of microcracks (e.g., a plurality of microcracks) and have less resistance to microcracking compared to cured lightning strike protection composite structures 80 (e.g., co-cured lightning strike protection composite structures 80a) having lightning strike protection material assemblies 10 (e.g., cured lightning strike protection material assemblies 10c), and the microcracks formed can extend into the structural plies of the composite structure, potentially increasing degradation of the composite structure. Thus, the cured lightning strike protection composite structures 80 (e.g., co-cured lightning strike protection composite structures 80a) minimize potential in-service degradation of the lightning strike protection material assemblies 10 (e.g., cured lightning strike protection material assemblies 10c), allowing them to be effective as needed.

[0111] As further shown in FIG. 3B , the cured lightning strike protection composite structures 80 (e.g., co-cured lightning strike protection composite structures 80a) include a laminate assembly 106 (e.g., in the form of a cured laminate assembly 106c) including the lightning strike protection material assemblies 10 (e.g., in the form of cured lightning strike protection material assemblies 10c) co-cured with and bonded to the structural assemblies 71 (e.g., composite laminate assemblies 72, e.g., in the form of cured composite laminate assemblies 72c). FIG. 3B shows the lightning strike protection material system 12 in the form of a cured lightning strike protection material system 12c after or following co-curing 14a (see FIG. 3B ).

[0112] As further shown in FIG. 3B , the impregnated resin 45 (e.g., in the form of a cured impregnated resin 45c) encapsulates the lightning strike expanding metal foil 18 and is also in the resin-impregnated mesh layer 42. As further shown in FIG. 3B , the composite laminate assemblies 72 (e.g., cured composite laminate assemblies 72c) have a plurality of structural plies 74 (e.g., a plurality of structural ply layers 75) with a structural resin 70 (e.g., in the form of a cured structural resin 70c).

[0113] Referring now to FIG. 3B , FIG. 3B is a graphical illustration showing a plot 132 of viscosity 60 or thickness along the y-axis 134 versus temperature 114 along the x-axis 136 during curing or co-curing of an exemplary lightning strike protection material system 12 (see FIG. 4 ) of the present disclosure, in which the lightning strike protection material system 12 has an impregnated resin 45 (see FIG. 4) and structural resin 70 (see FIG. 1B In graph 132, viscosity 60 decreases from top to bottom along y-axis 134, and temperature 114 increases from left to right along x-axis 136.

[0114] FIG. 1B Impregnation resin curve 138 and structural resin curve 140 are shown. Impregnation resin curve 138 represents impregnation resin 45 that undergoes rapid curing process 15 (see FIG. 1B ) with custom viscosity 60a (see FIG. 1B ), custom curing profile 62a (see FIG. 4 ), and custom rheology 64a (see FIG. 4 ). Structural resin curve 140 represents structural resin 70 (see FIG. 4 ) with structural resin viscosity 60b (see FIG. 1A ), structural resin curing profile 62b (see FIG. 1A ), and structural resin rheology 64b (see FIG. 2A ) that are different from custom viscosity 60a, custom curing profile 62a, and custom rheology 64a of impregnation resin 45.

[0115] As shown in FIG. 1A , impregnation resin curve 138 has a high or large starting point 142 of viscosity 60 or thickness. As further shown in FIG. 1A , as temperature 114 increases, viscosity 60 or thickness initially decreases to midpoint 144, and at midpoint 144, as temperature 114 continues to increase, viscosity 60 then begins to steadily increase from midpoint 144 to endpoint 146, and as curing or co-curing continues, impregnation resin 45 cures or co-cures to a hardened state or solid state. As shown in FIG. 1A , impregnation resin curve 138 has a U-shape 148.

[0116] As further shown in FIG. 1A , structural resin curve 140 has a high or large starting point 150 of viscosity 60 or thickness. As further shown in FIG. 1A , as temperature 114 increases, viscosity 60 or thickness decreases to midpoint 152, and at midpoint 152, as temperature 114 continues to increase, viscosity 60 then continues to slightly decrease and gently decreases from midpoint 152 to endpoint 154, and as curing or co-curing continues, structural resin cures or co-cures to a hardened state or solid state. As shown in FIG. 1A , structural resin curve 140 has a generally downwardly shaped curve 155.

[0117] As further shown in FIG. 1AAs further shown, there is a large or very large viscosity difference 156 between the viscosity 60 at the end point 146 of the impregnation resin curve 138 and the viscosity 60 at the sloping point 158 ​​on the structural resin curve 140. The large viscosity difference 156 during curing or co-curing prevents or minimizes the mixing of the impregnation resin 45 and the structural resin 70.

[0118] Now for reference FIG. 1A , FIG. 1A This is a graph 160 illustrating the viscosity 60 or thickness along the y-axis 134 versus the temperature 114 along the x-axis 136 during the curing or co-curing of a prior art known resin system for use in lightning protection material systems having known resins and known structured laminates that do not have custom viscosity, custom curing profiles, or custom rheological properties. In graph 160, the viscosity 60 decreases from top to bottom along the y-axis 134, and the temperature 114 increases from left to right along the x-axis 136.

[0119] FIG. 1A Resin profile 162 and structural laminate resin profile 164 are shown. Resin profile 162 indicates the absence of resins similar to impregnating resin 45 (see [link]). FIG. 1A A known resin with custom viscosity, custom curing profile, and / or custom rheological properties, wherein the known resin has the same viscosity, curing profile, and rheological properties as a known structured laminated resin, and does not undergo a rapid curing process.15 (see [reference]) FIG. 1A Curve 164 for structural laminates represents known structural laminates.

[0120] like FIG. 1A As shown, resin curve 162 has a starting point 166 with a viscosity of 60 or a high or large thickness. (As...) FIG. 1B As further shown, as the temperature 114 increases, the viscosity 60 or thickness decreases to the midpoint 168, and at the midpoint 168, as the temperature 114 continues to increase, the viscosity 60 then continues to decrease slightly and gradually decreases from the midpoint 168 to the endpoint 170, and as curing or co-curing continues, the resin cures or co-cures to a hardened or solid state. FIG. 2B As shown, resin curve 162 has a generally downward-shaped curve 155a.

[0121] like FIG. 1B As further shown, the structural laminate resin curve 164 has a starting point 172 with a viscosity of 60 or a high or large thickness. For example... FIG. 2BAs further illustrated, as the temperature 114 increases, the viscosity 60 or thickness decreases to the midpoint 174, and at the midpoint 174, as the temperature 114 continues to increase, the viscosity 60 then continues to decrease slightly and gradually decreases from the midpoint 174 to the endpoint 176, and as curing or co-curing continues, the structural laminate resin cures or co-cures to a hardened or solid state. FIG. 1B As shown, the structural laminate resin curve 164 has a generally downward-shaped curve 155b.

[0122] like FIG. 1B As further shown, there is a small viscosity difference 178 between the viscosity 60 at point 180 near the endpoint 170 of the resin curve 162 and the viscosity 60 at point 182 near the endpoint 176 of the structured laminate resin curve 164. This small viscosity difference 178 during curing or co-curing promotes the mixing of the known resin and the known structured laminate resin.

[0123] Now for reference FIG. 1B , FIG. 1B This is an illustration of a flowchart of an exemplary version of method 190 of this disclosure. In another version of this disclosure, a lightning protection material system 12, discussed in detail above, is provided (see...). FIG. 1B Method 190, for curing lightning protection composite material structures 80 (see) FIG. 1B Provides increased resistance to microcracking 82 (see...) FIG. 1B ) and resistance to degradation 84 (see FIG. 1B ). FIG. 1B The boxes in the diagram represent operations and / or parts or elements of operations, and the lines connecting the various boxes do not imply any particular order or dependency of operations or parts or elements of operations. FIG. 1B The disclosure of the steps of Method 190 as described herein should not be construed as requiring a predetermined order of execution. Rather, while an illustrative order is indicated, it should be understood that the order of steps can be modified as appropriate. Thus, some operations may be performed in a different order or simultaneously.

[0124] like FIG. 1B As shown, method 190 includes step 192: providing a lightning protection material system 12. As discussed in detail above, the lightning protection material system 12 includes a lightning protection material assembly 10 (see...). FIG. 4 As discussed in detail above, the lightning protection material assembly 10 includes a lightning-expanded metal foil layer 16 (see above). FIG. 1B , ​ The lightning-expanded metal foil layer 16 includes a lightning-expanded metal foil 18 (see...). ​ , ​ ).

[0125] Step 192 of providing the lightning protection material system 12 further includes providing the lightning protection material system 12 with a lightning protection material component 10, wherein, such as ​ As shown, the lightning-expanded metal foil 18 includes a discontinuous metal foil 26, which includes one or more of the following: perforated metal foil 28, expanded metal foil 29, metal mesh 30, metallized fiber mesh 31, metal screen 32, metallized fiber fabric 33, woven metal 34, metal wire mesh 35, metal foam 36, open-cell metal foam 36a, or another suitable discontinuous metal foil 26.

[0126] Step 192 of providing the lightning protection material system 12 further includes providing the lightning protection material system 12 with a lightning protection material component 10, wherein, such as ​ As shown, the lightning-expanded metal foil 18 also includes a metal material 38, which includes one or more of the following: copper 38a, aluminum 38b, titanium 38c, nickel 38d, gold 38e, silver 38f, or another suitable metal material 38, or as... ​ As shown, the lightning-expanded metal foil 18 also includes a metal alloy material 40, which includes one or more of the following: copper alloy 40a, aluminum alloy 40b, titanium alloy 40c, nickel alloy 40d, gold alloy 40e, silver alloy 40f, bronze 40g, brass 40h, or another suitable metal alloy material.

[0127] As discussed in detail above, the lightning protection material assembly 10 also includes a resin-impregnated mesh layer 42 laminated to the lightning-expanded metal foil layer 16 (see above). ​ , ​ The resin-impregnated mesh layer 42 includes a layer impregnated with impregnating resin 45 (see [link]). ​ ) non-metallic mesh fabric 44 (see ​ The impregnating resin 45 has a viscosity of 60 (see...). ​ For example, a custom viscosity of 60a (see...) ​ ); Curing curve 62 (see ​ For example, custom curing curve 62a (see...) ​ ); and rheological property 64 (see ​ For example, custom rheology 64a (see...) ​ ).

[0128] Step 192 of providing the lightning protection material system 12 further includes providing the lightning protection material system 12 with a lightning protection material component 10, wherein, such as ​As shown, the impregnating resin 45 includes a thermosetting resin 58, which includes one or more of the following: adhesive 58a, epoxy resin 58b, phenolic resin 58c, polyimide 58d, bismaleimide 58e, polyurethane 58f, fluoropolymer 58g, cyanate ester 58h, or another suitable thermosetting resin 58.

[0129] As discussed in detail above, the lightning protection material system 12 also includes a composite laminate assembly 72 (see above). ​ , ​ ), for example, uncured composite laminate assembly 72a (see ​ , ​ ), which is pre-impregnated with structural resin 70 (see ​ Multiple structural layers 74 (see) ​ (For example, multiple structural layers 75 (see)) ​ Composed of. For example... ​ As shown, the structural resin 70 has a custom viscosity 60a, a custom curing curve 62a, and a custom rheological property 64a that are different from those of the impregnating resin 45.

[0130] Multiple structural layers 75 each include composite material 90 (see ​ ),like ​ As shown, the composite material 90 includes one or more of the following: one or more carbon fiber reinforced polymer (CFRP) 94 or plastics; one or more glass fiber reinforced polymer (GFRP) 96 or plastics; or one or more aromatic polyamide polymers 100 (see...). ​ ); or another suitable composite material 90. Composite material 90 includes composite fibers 92 (see ​ ), for example, carbon fiber 95 (see ​ ), glass fiber 98 (see) ​ ), Aromatic polyamide fiber 102 (see ​ ) or other suitable composite fibers 92. For example ​ As shown, the structural resin 70 includes a thermosetting structural resin 104, which includes one or more of the following: epoxy structural resin 104a, phenolic structural resin 104b, polyimide structural resin 104c, bismaleimide structural resin 104d, polyurethane structural resin 104e, fluoropolymer structural resin 104f, cyanate ester structural resin 104g, or another suitable thermosetting structural resin 104.

[0131] like ​ As shown, method 190 also includes step 194: via laying process 73a (see...) ​ ) Lightning protection material component 10 (seeFIG. 1A , FIG. 2B ) Lay 73 (see FIG. 1B In uncured composite laminate assembly 72a (see...) FIG. 1B , FIG. 2B )superior.

[0132] like FIG. 4 As shown, method 190 further includes step 196: in heating device 108 (see...) FIG. 2C (For example, autoclave 110 (see)) FIG. 2C In the process of curing 14a or curing 14 in an uncured composite laminate component 72a using heat 112 (see...) FIG. 2C Lightning protection material component 10 on ) (see FIG. 2C ), and during co-curing 14a or curing 14, structural resin 70 (see FIG. 1B , FIG. 2C ) and impregnation resin 45 (see FIG. 1A , FIG. 2C ) does not mix and provides defined resin boundaries 78 (see FIG. 2C Furthermore, the impregnated resin 45 effectively encapsulates the lightning-expanded metal foil 18 (see...). FIG. 2C ).

[0133] Preferably, the lightning protection material assembly 10 (e.g., uncured lightning protection material assembly 10a) and the composite laminate assembly 72 (see...) FIG. 1B (For example, the uncured composite laminate component 72a) undergoes co-curing 14a or curing 14, which is a rapid curing process 15 (see...) FIG. 1B (e.g., disclosed in U.S. Patent No. 11,752,708B2, which is incorporated herein by reference in its entirety.)

[0134] Step 196, which involves co-curing 14a or curing 14a onto the uncured composite laminate 72a using heat 112 in autoclave 110, further includes: initially heating the uncured composite laminate 72a to temperature 114 (see...). FIG. 1B (For example, initial temperature 114a (see...) FIG. 1B To generate a partially cured composite laminate assembly 72b (see...) FIG. 1B The initial heating is sufficient to gel the uncured impregnating resin 45, but insufficient to gel the uncured structural resin 70; and the partially cured composite laminate 72b is subsequently heated to a final temperature 114c greater than the initial temperature 114a (see...). FIG. 1B ), to generate a cured lightning protection composite material structure 80 (see FIG. 1B , FIG. 2D), wherein the combination of the initial heating and the subsequent heating is sufficient to fully cure both the infused resin 45 and the structural resin 70.

[0135] The co-curing 14a or curing 14 of the step 196 (wherein the lightning strike protection material assembly 10 on the uncured composite laminate assembly 72a is co-cured 14a in the autoclave 110 using heat 112) further includes applying pressure 118 (see FIG. 1B ) to at least one of: the uncured composite laminate assembly 72a during the initial heating; or the partially cured composite laminate assembly 72b during the subsequent heating.

[0136] As shown in FIG. 4 , the method 190 further includes a step 198 of obtaining a cured lightning strike protection composite material structure 80 (see FIG. 1B , FIG. 2D ) (e.g., a co-cured lightning strike protection composite material structure 80a (see FIG. 1B )) formed from the co-curing 14a or curing 14 of the lightning strike protection material assembly 10 (see FIG. 1A , FIG. 2A ) (e.g., the uncured lightning strike protection material assembly 10a (see FIG. 1A , FIG. 2A )) and the composite laminate assembly 72 (e.g., the uncured composite laminate assembly 72a (see FIG. 1B , FIG. 2B )), and using the lightning strike protection material system 12 to provide the cured lightning strike protection composite material structure 80 (e.g., the co-cured lightning strike protection composite material structure 80a) with increased microcracking resistance 82 and degradation resistance 84 and to provide the lightning strike protection function 11.

[0137] The step 198 of obtaining the cured lightning strike protection composite material structure 80 (e.g., the co-cured lightning strike protection composite material structure 80a) further includes obtaining the cured lightning strike protection composite material structure 80 (e.g., the co-cured lightning strike protection composite material structure 80a) including a composite material structure 120 (see FIG. 1B ), e.g., an aircraft composite material structure 120a (see FIG. 1B ), e.g., including a panel 122 (see FIG. 1B ), e.g., being one of: a wing 204 (see FIG. 5 ) of the aircraft 200a (see FIG. 1B , FIG. 5 ) (see FIG. 1B , FIG. 5 ) of the aircraft 200a (see FIG. 5horizontal stabilizer panel 122b (see FIG. 1B , horizontal stabilizer panel 122b (see FIG. 5 ) of the horizontal stabilizer 212 (see FIG. 1B ) of the aircraft 200a (see FIG. 5 ) of the fuselage 202 (see FIG. 1B , horizontal stabilizer panel 122b (see FIG. 5 ) of the horizontal stabilizer 212 (see FIG. 1B ) of the aircraft 200a (see

[0138] Referring now to FIG. 5 , FIG. 5 is an illustration of an isometric view of a vehicle 200 (e.g., an aircraft 200a) incorporating an exemplary cured lightning strike protection composite structure 80 (see also FIG. 1B , FIG. 2D , FIG. 2E ) (e.g., an exemplary co-cured lightning strike protection composite structure 80a (see also FIG. 1B , FIG. 2D , FIG. 2E )) having a lightning strike protection material system 12 (see FIG. 1B , FIG. 2B ) of the present disclosure, in a composite structure 120 (e.g., an aircraft composite structure 120a). As shown in FIG. 5 , the vehicle 200 (e.g., the aircraft 200a) includes a fuselage 202, wings 204, engines 206, and a tail 208. As shown in FIG. 5 , the tail 208 includes a vertical stabilizer 210 and a horizontal stabilizer 212.

[0139] As shown in FIG. 5 , the cured lightning strike protection composite structure 80 (e.g., the co-cured lightning strike protection composite structure 80a) can include or be part of a composite structure 120 (e.g., an aircraft composite structure 120a) in the form of a panel 122, such as a wing panel 122a of a wing 204 of the aircraft 200a. The cured lightning strike protection composite structure 80 (e.g., the co-cured lightning strike protection composite structure 80a) can include or be part of a composite structure 120 (e.g., an aircraft composite structure 120a) in the form of a panel 122, such as a horizontal stabilizer panel 122b (see FIG. 5 ) of the horizontal stabilizer 212 (see FIG. 5 ) of the aircraft 200a (see FIG. 1B ), or such as a fuselage panel 122c (see FIG. 5 ) of the fuselage 202 (see FIG. 5) or another suitable composite structure 120 or another suitable aircraft composite structure 120a. FIG. 1B

[0140] The composite structure 120 (e.g., the aircraft composite structure 120a, which includes the wing panel 122a, the horizontal stabilizer panel 122b, the fuselage panel 122c, or another suitable aircraft panel) can include a composite structure 120 (e.g., the aircraft composite structure 120a) made from a composite material 90 (see FIG. 1B ) such as a carbon fiber reinforced polymer (CFRP) 94 (see FIG. 1B ) or a carbon fiber reinforced plastic; a glass fiber reinforced polymer (GFRP) 96 (see FIG. 1B ) or a glass fiber reinforced plastic; or an aramid polymer 100 (see FIG. 1B ); or another type of composite material 90. The cured lightning strike protected composite structure 80 (e.g., the co-cured lightning strike protected composite structure 80a) with the lightning strike protection material system 12 (see FIG. 1B , FIG. 2D ) can be used on an aerospace surface (e.g., the wing 204, the horizontal stabilizer 212, the fuselage 202, or another aerospace surface area of the aircraft 200a) to provide increased microcracking resistance 82 (see FIG. 1B ), degradation resistance 84 (see FIG. 1B ), and lightning strike protection functionality 11 (see FIG. 1B ).

[0141] FIG. 5 Further shown is a lightning strike 214 hitting the wing 204, the cured lightning strike protected composite structure 80 (e.g., the co-cured lightning strike protected composite structure 80a) providing lightning strike protection functionality 11 (see FIG. 1B ) to the underlying structural assembly 71 (see FIG. 1B ) (e.g., the composite laminate assembly 72 (see FIG. 1B ), the cured lightning strike protected composite structure 80 having the lightning strike protection material system 12 (see FIG. 1B ) and the lightning strike protection material assembly 10 (see FIG. 1B ), and being part of or including the composite structure 120 (e.g., the aircraft composite structure 120a).

[0142] Although the aircraft 200a shown in FIG. 5 is generally representative of a commercial passenger aircraft having one or more aircraft composite structures 120a, the lightning strike protection material assembly 10 (see FIG. 1A ), the lightning strike protection material system 12 (see​FIG. 1B ) and Method 190 (see FIG. 4 The publicly available teachings can be applied to the composite material structure 120a of other passenger aircraft. Additionally, lightning protection material component 10 (see...) FIG. 1A The teachings of the disclosed versions of the lightning protection material system 12 and method 190 can be applied to composite material structures 120a for cargo aircraft, military aircraft, rotorcraft and other types of aircraft or aircraft, as well as aerospace vehicles, spacecraft, satellites, space launchers, rockets and other aerospace vehicles. Furthermore, the lightning protection material assembly 10 (see...) FIG. 1A The teachings of the disclosed versions of the lightning protection material system 12 and method 190 can be applied to composite material structures 120, such as ships, automobiles, trains, building structures or other suitable vehicles or structures.

[0143] Now for reference FIG. 6 and FIG. 7 , FIG. 6 This is an illustration of a flowchart of an exemplary aircraft manufacturing and maintenance method 300, and FIG. 7 This is an illustration of an exemplary block diagram of aircraft 320. (Reference) FIG. 6 and FIG. 7 It is possible to do as FIG. 6 The aircraft manufacturing and maintenance method 300 shown, and as such FIG. 7 Versions of this disclosure are described in the context of the aircraft 320 shown.

[0144] During pre-production, the exemplary aircraft manufacturing and maintenance method 300 may include the specification and design 302 of the aircraft 320 and material procurement 304. During manufacturing, the production of components and sub-assemblies of the aircraft 320 is carried out 306, and system integration 308 is performed. Subsequently, the aircraft 320 may undergo certification and delivery 310 for entry into service 312. Upon entry into service by the customer 312, the aircraft 320 may be scheduled for regular maintenance and repairs 314 (which may also include modifications, reconfigurations, refurbishments, and other suitable repairs).

[0145] Each process of the aircraft manufacturing and maintenance method 300 can be performed or executed by a systems integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this description, a systems integrator can include, but is not limited to, any number of aircraft manufacturers and major systems subcontractors. A third party can include, but is not limited to, any number of vendors, subcontractors, and suppliers. An operator can include airlines, leasing companies, military entities, service organizations, and other suitable operators.

[0146] like FIG. 7As shown, an aircraft 320 produced by the exemplary aircraft manufacturing and maintenance method 300 may include a fuselage 322 having multiple systems 324 and an interior 326. Examples of the multiple systems 324 may include one or more of a propulsion system 328, an electrical system 330, a hydraulic system 332, and an environmental system 334. Any number of other systems may be included. Although an aerospace example is shown, the principles of this disclosure can be applied to other industries, such as the automotive industry.

[0147] The methods and systems embodied herein can be employed during any or more stages of the aircraft manufacturing and maintenance method 300. For example, a component or sub-component corresponding to component and sub-component manufacturing 306 can be produced or manufactured in a manner similar to that of a component or sub-component produced while the aircraft 320 is in service 312. Furthermore, one or more device embodiments, method embodiments, or combinations thereof can be utilized during component and sub-component manufacturing 306 and system integration 308, for example, by significantly accelerating the assembly of the aircraft 320 or reducing the cost of the aircraft 320. Similarly, one or more device embodiments, method embodiments, or combinations thereof can be utilized while the aircraft 320 is in service 312, for example, but not limited to repair and maintenance 314.

[0148] Lightning protection material component 10 (see FIG. 1A ), Lightning protection material system 12 (see FIG. 1B ) and Method 190 (see FIG. 4 The publicly available version of the anti-impregnation resin 45 (see) FIG. 1A ) or lightning protection material resin 46 (see FIG. 1A ) and the following structural component 71 (see FIG. 1B (e.g., composite laminate component 72) structural resin 70 (see) FIG. 1B ) in co-cured 14a (see FIG. 1B ) or cure for 14 (see FIG. 1B During mixing, areas where the two different materials are in close proximity to each other should be avoided, and co-curing should be carried out for 14 years (see [link to documentation]). FIG. 1B ) or cure for 14 (see FIG. 1B Provide sufficient impregnation resin 45 during the process (see) FIG. 1A ) or lightning protection material resin 46 (see FIG. 1A ), to effectively encapsulate the lightning protection metal foil layer 16 (see FIG. 1A Lightning-induced expansion of metal foil 18 (see...) FIG. 1A ).

[0149] Additionally, lightning protection material component 10 (see...) FIG. 1B ), Lightning protection material system 12 (see FIG. 4 ) and Method 190 (seeFIG. 2E The published version of ) mitigates, minimizes, and / or prevents microcracks and microfractures 83 (see FIG. 1B It also has increased resistance to microcracks 82 (see FIG. 1B It also provides resistance to degradation 84 (see FIG. 1B ), to prevent degradation to the underlying composite laminate 72 (e.g., cured composite laminate 72c (see FIG. 1A This avoids costly repairs or rework.

[0150] In addition, lightning protection material component 10 (see FIG. 1B ), Lightning protection material system 12 (see FIG. 4 ) and Method 190 (see FIG. 1A The publicly available version provides a feature with lightning-expanded metal foil 18 (see...). FIG. 1A The relevant controlled resin viscosity or custom viscosity 60a (see...) FIG. 1A ), controlled curing profile or custom curing profile 62a (see FIG. 1A ) and custom rheology 64a (see FIG. 1A A novel impregnation resin 45 (see) FIG. 1A (For example, thermosetting resin 58 (see...) FIG. 1A At the same time, ensure that the structural resin 70 is in contact with the impregnating resin 45 or the lightning protection material resin 46 (see...). FIG. 1A Chemical compatibility between 66 (see 66) FIG. 1A ) and adhesion strength 68 (see FIG. 1B Furthermore, the custom viscosity 60a, custom curing profile 62a, and custom rheology 64a of the impregnating resin 45 differ from the structural resin viscosity 60b of the structural resin 70 (see [link to documentation]). FIG. 1B ), Curing curve of structural resin 62b (see FIG. 1B ) and structural resin rheology 64b (see FIG. 1A This prevents the structural resin 70 from reacting with the impregnating resin 45 or the lightning protection material resin 46 (see...). FIG. 1A The mixture of lightning protection materials 10 disclosed herein (see...) FIG. 1B ) and lightning protection material system 12 (see FIG. 1B Cured lightning protection composite material structure 80 (see) FIG. 1B (For example, co-cured lightning protection composite material structure 80a (see...) FIG. 1A Improved resistance to thermal and humid cycling microcracks is provided in co-cured laminates (e.g., cured lightning protection composite structure 80, e.g., co-cured lightning protection composite structure 80a) that have structural components and lightning protection components.

[0151] Use non-metallic mesh fabric 44 (refer to)FIG. 1A The impregnating resin 45 is mixed with the lightning-expanded metal foil 18 (see...). FIG. 1B Lamination. Composite laminate assembly 72 (see...) FIG. 1A ) and lightning protection material assembly 10 (see FIG. 1B Co-curing or curing to produce or form a composite material structure 120, such as a cured lightning protection composite material structure 80 (see...). FIG. 1B For example, co-cured lightning protection composite material structure 80a (see...) FIG. 1B The composite laminate assembly 72 includes multiple structural layers 74 (see...). FIG. 1B For example, multiple structural layers 75 (see FIG. 1B Structural layer 74 is made of composite material 90 (see...) FIG. 1B It is made and pre-impregnated with structural resin 70 (see FIG. 1B ), composite material 90 is, for example: carbon fiber reinforced polymer (CFRP) 94 (see FIG. 1B ) or carbon fiber reinforced plastic; or glass fiber reinforced polymer (GFRP) 96 (see FIG. 1A ) or glass fiber reinforced plastic; or aromatic polyamide polymer 100 (see FIG. 1B Furthermore, the initial custom viscosity of impregnating resin 45 is 60c (see...). FIG. 1B The initial structural resin viscosity 60d can be significantly different from that of structural resin 70 (see [link]). FIG. 1B ), so that the impregnating resin 45 and the structural resin 70 are initially cured 14b (see FIG. 2C ) or initial co-cured 14c (see FIG. 1B Mixing during the process is minimized. For example, during co-curing 14a, the impregnating resin 45 in the non-metallic mesh 44 is forced into the opening 130 of the lightning-expanded metal foil 18 (see...). FIG. 1B In this process, the impregnating resin 45 completely encapsulates or completely surrounds the lightning-expanded metal foil 18. The customized curing profile 62a of the impregnating resin 45 is obtained at a lower temperature 114 (see [reference]). FIG. 1B Crosslinking is initiated under these conditions, thereby rapidly increasing the custom viscosity 60a of the impregnating resin 45, allowing the impregnating resin 45 to pass through encapsulation 76 (see...). FIG. 2D This effectively encapsulates the lightning-expanded metal foil 18 while maintaining the separation and non-mixing of the impregnating resin 45 and the structural resin 70. These differences prevent the mixing of the two resins (i.e., the impregnating resin 45 and the structural resin 70) during curing or co-curing, thereby ensuring a distinct resin layer and defined resin boundary 78 (see [reference]) in the co-cured panel (e.g., a cured lightning protection composite structure 80, e.g., a co-cured lightning protection composite structure 80a). FIG. 2E , FIG. 1A). The result is significantly less surface porosity and improved performance in thermal-hygroscopic cycling, which is achieved by fewer microcracks 83 (see FIG. 1B ) in the cured lightning strike protection composite structure 80 (e.g., co-cured lightning strike protection composite structure 80a) after exposure to thermal-hygroscopic cycling. The lack of mixing of the two resins (i.e., impregnation resin 45 and structural resin 70) reduces damage to the two resins (i.e., impregnation resin 45 and structural resin 70) caused by different coefficients of thermal expansion (CTE) 86a, 86b and different coefficients of moisture expansion (CME) 88a, 88b between the two resins (i.e., impregnation resin 45 and structural resin 70).

[0152] In addition, the disclosed versions of the lightning strike protection material assembly 10 (see FIG. 4 ), the lightning strike protection material system 12 (see FIG. 1B ), and the method 190 (see FIG. 1A ) provide environmental protection for a product with lightning strike protection on a structural composite or composite structure 120 (see FIG. 1B ), such as a cured lightning strike protection composite structure 80, e.g., co-cured lightning strike protection composite structure 80a. The disclosed versions of the lightning strike protection material assembly 10 (see FIG. 4 ), the lightning strike protection material system 12 (see FIG. 1B ), and the method 190 (see FIG. 1A ) prevent premature aging damage to the product (e.g., cured lightning strike protection composite structure 80, e.g., co-cured lightning strike protection composite structure 80a) caused by thermal-hygroscopic cycling, thereby ensuring non-degradation and anti-degradation properties 84 (see FIG. 1B ) of the lightning strike protection material assembly 10 and the lightning strike protection material system 12. Furthermore, the disclosed versions of the lightning strike protection material assembly 10 (see FIG. 4 ), the lightning strike protection material system 12 (see FIG. 1A ), and the method 190 (see FIG. 1B ) can extend the period between in-service product coating maintenance and reduce the likelihood of damage due to in-service thermal-hygroscopic cycling in a composite with lightning strike protection material. Depending on the resin composition of the impregnation resin 45, the impregnation resin 45 can also have structural, adhesive, or electrical properties that can be utilized. Moreover, the disclosed versions of the lightning strike protection material assembly 10 (see FIG. 4 ), the lightning strike protection material system 12 (see ​ ), and the method 190 (see ​ ) can allow for a reduction in the evaluation period of newly proposed systems to ensure that new and better systems can be implemented more quickly and minimize production and in-service issues.

[0153] Many modifications and other versions of the disclosure will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing description and the associated drawings. The versions described herein are intended to be illustrative, and not limiting, or exhaustive. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Functionally equivalent methods and apparatuses, in addition to those enumerated herein, are possible within the scope of the disclosure. Such modifications and variations are intended to fall within the scope of the appended claims. The disclosure is limited only by the terms of the claims and the full scope of equivalents for which the claims are entitled.

[0154] Examples of the disclosure can be described according to one or more of the following clauses.

[0155] Clause 1. A lightning strike protection material assembly, comprising:

[0156] a lightning strike expanding metal foil layer comprising a lightning strike expanding metal foil; and

[0157] a resin-impregnated scrim layer laminated to the lightning strike expanding metal foil layer, the resin-impregnated scrim layer comprising a non-metallic scrim impregnated with an impregnation resin having a custom viscosity and a custom cure profile,

[0158] wherein the lightning strike protection material assembly is configured for laying up on and co-curing with an uncured composite laminate assembly comprised of a plurality of structural ply layers pre-impregnated with a structural resin having a structural resin viscosity and a structural resin cure profile different from the custom viscosity and the custom cure profile of the impregnation resin to prevent the structural resin and the impregnation resin from mixing during co-curing to allow the impregnation resin to effectively encapsulate the lightning strike expanding metal foil and provide a defined resin boundary, and

[0159] further wherein a cured lightning strike protection composite structure is formed from the co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly and has lightning strike protection functionality and increased resistance to micro-cracking and degradation.

[0160] Clause 2. The lightning strike protection material assembly of Clause 1, wherein the lightning strike expanding metal foil comprises a non-continuous metal foil comprising one or more of: a perforated metal foil, an expanded metal foil, a metal mesh, a metalized fiber mesh, a metal screen, a metalized fiber fabric, a woven metal, a wire mesh, a metal foam, and an open cell metal foam.

[0161] Clause 3. The lightning strike protection material assembly of Clause 1, wherein the lightning strike expanding metal foil comprises:

[0162] a metallic material comprising one or more of copper, aluminum, titanium, nickel, gold, and silver; or

[0163] a metallic alloy material comprising one or more of a copper alloy, an aluminum alloy, a titanium alloy, a nickel alloy, a gold alloy, a silver alloy, a bronze, and a brass.

[0164] Clause 4. The lightning strike protection material assembly of Clause 1, wherein the non-metallic scrim comprises one of a non-metallic scrim mat, a fiberglass scrim mat, a carbon fiber scrim mat, a woven scrim mat, a knitted polyester scrim mat, or a non-woven scrim mat.

[0165] Clause 5. The lightning strike protection material assembly of Clause 1, wherein the impregnated resin comprises a thermoset resin comprising one or more of an adhesive, an epoxy, a phenolic, a polyimide, a bismaleimide, a polyurethane, a fluoropolymer, and a cyanate ester.

[0166] Clause 6. The lightning strike protection material assembly of Clause 1, wherein the customized viscosity and customized cure profile of the impregnated resin are related to the lightning strike expanding metal foil and provide chemical compatibility and adhesive capability between the impregnated resin and the structural resin.

[0167] Clause 7. A lightning strike protection material system, the lightning strike protection material system comprising:

[0168] a lightning strike protection material assembly comprising a lightning strike expanding metal foil layer comprising a lightning strike expanding metal foil and a resin-impregnated scrim layer laminated to the lightning strike expanding metal foil layer, the resin-impregnated scrim layer comprising a non-metallic scrim impregnated with an impregnated resin having a customized viscosity and a customized cure profile; and

[0169] an uncured composite laminate assembly comprised of a plurality of structural ply layers pre-impregnated with a structural resin having a structural resin viscosity and a structural resin cure profile different than the customized viscosity and the customized cure profile of the impregnated resin,

[0170] wherein the lightning strike protection material assembly is laid up on and co-cured with the uncured composite laminate assembly, and during co-curing, the structural resin and the impregnated resin do not mix and provide a defined resin boundary, and the impregnated resin effectively encapsulates the lightning strike expanding metal foil, and

[0171] Further wherein the cured lightning strike protection composite structure is formed from co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly, and the cured lightning strike protection composite structure has lightning strike protection functionality, and has increased micro-cracking resistance and degradation resistance.

[0172] Clause 8. The lightning strike protection material system of Clause 7, wherein the lightning strike expanding metal foil comprises a discontinuous metal foil comprising one or more of: a perforated metal foil, an expanding metal foil, a metal mesh, a metalized fiber mesh, a metal screen, a metalized fiber fabric, a woven metal, a wire mesh, a metal foam, and an open cell metal foam.

[0173] Clause 9. The lightning strike protection material system of Clause 7, wherein the lightning strike expanding metal foil comprises:

[0174] a metal material comprising one or more of copper, aluminum, titanium, nickel, gold, and silver; or

[0175] a metal alloy material comprising one or more of a copper alloy, an aluminum alloy, a titanium alloy, a nickel alloy, a gold alloy, a silver alloy, a bronze, and a brass.

[0176] Clause 10. The lightning strike protection material system of Clause 7, wherein the non-metallic scrim comprises one of a non-metallic scrim mat, a fiberglass scrim mat, a carbon fiber scrim mat, a woven scrim mat, a knitted polyester scrim mat, or a non-woven scrim mat.

[0177] Clause 11. The lightning strike protection material system of Clause 7, wherein the impregnated resin comprises a thermoset resin comprising one or more of an adhesive, an epoxy resin, a phenolic, a polyimide, a bismaleimide, a polyurethane, a fluoropolymer, and a cyanate ester.

[0178] Clause 12. The lightning strike protection material system of Clause 7, wherein each of the plurality of structural ply layers comprises a composite material comprising one of one or more carbon fiber reinforced polymers, one or more glass fiber reinforced polymers, or one or more aramid polymers.

[0179] Clause 13. The lightning strike protection material system of Clause 7, wherein the structural resin comprises a thermoset structural resin comprising one or more of an epoxy structural resin, a phenolic structural resin, a polyimide structural resin, a bismaleimide structural resin, a polyurethane structural resin, a fluoropolymer structural resin, and a cyanate ester structural resin.

[0180] Clause 14. The lightning strike protection material system of Clause 7, wherein the cured lightning strike protection composite structure comprises one or more of: a wing panel of a wing of an aircraft; a horizontal stabilizer panel of a horizontal stabilizer of the aircraft; and a fuselage panel of a fuselage of the aircraft.

[0181] Clause 15. A method of using a lightning strike protection material system to provide increased microcracking resistance and protection against degradation for a cured lightning strike protection composite structure, the method comprising the steps of:

[0182] providing the lightning strike protection material system, the lightning strike protection material system comprising:

[0183] a lightning strike protection material assembly comprising: a lightning strike expansion metal foil layer comprising a lightning strike expansion metal foil; and a resin-impregnated scrim layer laminated to the lightning strike expansion metal foil layer, the resin-impregnated scrim layer comprising a non-metallic scrim impregnated with an impregnation resin, the impregnation resin having a customized viscosity and a customized cure profile; and

[0184] an uncured composite laminate assembly comprised of a plurality of structural ply layers pre-impregnated with a structural resin, the structural resin having a structural resin viscosity and a structural resin cure profile that are different from the customized viscosity and the customized cure profile of the impregnation resin;

[0185] laying up the lightning strike protection material assembly on the uncured composite laminate assembly;

[0186] co-curing the lightning strike protection material assembly on the uncured composite laminate assembly with heat in an autoclave, and during the co-curing, the structural resin and the impregnation resin do not mix and provide a defined resin boundary, and the impregnation resin effectively encapsulates the lightning strike expansion metal foil; and

[0187] obtaining the cured lightning strike protection composite structure formed from the co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly, and using the lightning strike protection material system to provide increased microcracking resistance and protection against degradation and lightning strike protection functionality for the cured lightning strike protection composite structure.

[0188] Clause 16. The method of Clause 15, wherein the step of providing the lightning strike protection material system further comprises: providing the lightning strike protection material system with the lightning strike protection material assembly, wherein the lightning strike expansion metal foil comprises:

[0189] a non-continuous metal foil comprising one or more of: a perforated metal foil, an expanded metal foil, a metal mesh, a metalized fiber mesh, a metal screen, a metalized fiber fabric, a woven metal, a wire mesh, a metal foam, and an open cell metal foam; and

[0190] Further wherein the lightning strike expanded metal foil comprises: a metal material comprising one or more of copper, aluminum, titanium, nickel, gold, and silver; or a metal alloy material comprising one or more of a copper alloy, an aluminum alloy, a titanium alloy, a nickel alloy, a gold alloy, a silver alloy, a bronze, and a brass.

[0191] Clause 17. The method of clause 15, wherein the step of providing the lightning strike protection material system further comprises: providing the lightning strike protection material system with the lightning strike protection material assembly, wherein the impregnated resin comprises a thermoset resin comprising one or more of: a glue, an epoxy, a phenolic, a polyimide, a bismaleimide, a polyurethane, a fluoropolymer, and a cyanate ester.

[0192] Clause 18. The method of clause 15, wherein the step of co-curing the lightning strike protection material assembly on the uncured composite laminate assembly in the autoclave with heat further comprises:

[0193] initially heating the uncured composite laminate assembly to an initial temperature to generate a partially cured composite laminate assembly, wherein the initial heating is sufficient to gel the uncured impregnated resin but insufficient to gel the uncured structural resin; and

[0194] subsequently heating the partially cured composite laminate assembly to a final temperature greater than the initial temperature to generate the cured lightning strike protection composite material structure, wherein the combination of the initial heating and the subsequent heating is sufficient to fully cure both the impregnated resin and the structural resin.

[0195] Clause 19. The method of clause 18, wherein the step of co-curing the lightning strike protection material assembly on the uncured composite laminate assembly in the autoclave with heat further comprises applying pressure to at least one of:

[0196] the uncured composite laminate assembly during the initial heating; and

[0197] the partially cured composite laminate assembly during the subsequent heating.

[0198] Clause 20. The method of clause 15, wherein the step of obtaining the cured lightning strike protection composite material structure further comprises obtaining the cured lightning strike protection composite material structure comprising one of: a wing panel of a wing of an aircraft; a horizontal stabilizer panel of a horizontal stabilizer of the aircraft; or a fuselage panel of a fuselage of the aircraft.

Claims

1. A lightning strike protection material assembly, the lightning strike protection material assembly comprising: a lightning strike expanding metal foil layer, the lightning strike expanding metal foil layer comprising a lightning strike expanding metal foil; and a resin-impregnated scrim layer, the resin-impregnated scrim layer being laminated to the lightning strike expanding metal foil layer, the resin-impregnated scrim layer comprising a non-metallic scrim impregnated with an impregnation resin, the impregnation resin having a custom viscosity and a custom cure profile, wherein the lightning strike protection material assembly is configured for laying up on and co-curing with an uncured composite laminate assembly, the uncured composite laminate assembly being comprised of a plurality of structural ply layers pre-impregnated with a structural resin, and the structural resin having a structural resin viscosity and a structural resin cure profile different from the custom viscosity and the custom cure profile of the impregnation resin to prevent the structural resin and the impregnation resin from mixing during co-curing to allow the impregnation resin to effectively encapsulate the lightning strike expanding metal foil and provide a defined resin boundary, and further wherein a cured lightning strike protection composite structure is formed from the co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly, and the cured lightning strike protection composite structure has lightning strike protection functionality and has increased resistance to micro-cracking and resistance to degradation. the lightning strike expanding metal foil comprises a discontinuous metal foil comprising one or more of: a perforated metal foil, an expanded metal foil, a metal mesh, a metalized fiber mesh, a metal screen, a metalized fiber fabric, a woven metal, a wire mesh, a metal foam, and an open cell metal foam.

2. The lightning strike protection material assembly of claim 1, wherein, the lightning strike expanding metal foil comprises:

3. The lightning strike protection material assembly of claim 1, wherein, a metal material comprising one or more of: copper, aluminum, titanium, nickel, gold, and silver; or a metal alloy material comprising one or more of: a copper alloy, an aluminum alloy, a titanium alloy, a nickel alloy, a gold alloy, a silver alloy, a bronze, and a brass. the non-metallic scrim comprises one of: a non-metallic scrim mat, a fiberglass scrim mat, a carbon fiber scrim mat, a woven scrim mat, a knitted polyester scrim mat, or a non-woven scrim mat.

4. The lightning strike protection material assembly of claim 1, wherein, the impregnation resin comprises a thermoset resin comprising one or more of: a glue, an epoxy, a phenolic, a polyimide, a bismaleimide, a polyurethane, a fluoropolymer, and a cyanate ester.

5. The lightning strike protection material assembly of claim 1, wherein, the custom viscosity and the custom cure profile of the impregnation resin are related to the lightning strike expanding metal foil and provide chemical compatibility and adhesive capability between the impregnation resin and the structural resin.

6. The lightning strike protection material assembly of claim 1, wherein, 7. A lightning strike protection material system, the lightning strike protection material system comprising: a lightning strike protection material assembly, the lightning strike protection material assembly comprising: a lightning strike expanding metal foil layer, the lightning strike expanding metal foil layer comprising a lightning strike expanding metal foil; and a resin-impregnated scrim layer, the resin-impregnated scrim layer being laminated to the lightning strike expanding metal foil layer, the resin-impregnated scrim layer comprising a non-metallic scrim impregnated with an impregnation resin, the impregnation resin having a custom viscosity and a custom cure profile; and a lightning strike protection material assembly, the lightning strike protection material assembly comprising: a lightning strike expanding metal foil layer, the lightning strike expanding metal foil layer comprising a lightning strike expanding metal foil; and a resin-impregnated scrim layer, the resin-impregnated scrim layer being laminated to the lightning strike expanding metal foil layer, the resin-impregnated scrim layer comprising a non-metallic scrim impregnated with an impregnation resin, the impregnation resin having a custom viscosity and a custom cure profile; and an uncured composite laminate assembly comprised of a plurality of structural ply layers pre-impregnated with a structural resin having a structural resin viscosity and a structural resin cure profile different than a custom viscosity and a custom cure profile of the impregnation resin, wherein the lightning strike protection material assembly is laid up on and co-cured with the uncured composite laminate assembly, and during co-curing, the structural resin and the impregnation resin do not mix and provide a defined resin boundary, and the impregnation resin effectively encapsulates the lightning strike expanding metal foil, and further wherein the cured lightning strike protection composite structure is formed from the co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly, and the cured lightning strike protection composite structure has lightning strike protection functionality, and has increased micro-cracking resistance and degradation resistance.

8. The lightning strike protection material system of claim 7, wherein, The lightning strike expanding metal foil includes a discontinuous metal foil including one or more of: a perforated metal foil, an expanding metal foil, a metal mesh, a metalized fiber mesh, a metal screen, a metalized fiber fabric, a woven metal, a wire mesh, a metal foam, and an open cell metal foam.

9. The lightning strike protection material system of claim 7, wherein, The lightning strike expanding metal foil includes: a metal material including one or more of: copper, aluminum, titanium, nickel, gold, and silver; or a metal alloy material including one or more of: a copper alloy, an aluminum alloy, a titanium alloy, a nickel alloy, a gold alloy, a silver alloy, a bronze, and a brass.

10. A method of using a lightning strike protection material system to provide increased micro-cracking resistance and degradation resistance to a cured lightning strike protection composite structure, the method comprising the steps of: providing the lightning strike protection material system, the lightning strike protection material system including: a lightning strike protection material assembly including: a lightning strike expanding metal foil layer including a lightning strike expanding metal foil; and a resin-impregnated scrim layer laminated to the lightning strike expanding metal foil layer, the resin-impregnated scrim layer including a non-metallic scrim impregnated with an impregnation resin having a custom viscosity and a custom cure profile; and an uncured composite laminate assembly comprised of a plurality of structural ply layers pre-impregnated with a structural resin having a structural resin viscosity and a structural resin cure profile different than a custom viscosity and a custom cure profile of the impregnation resin; laying up the lightning strike protection material assembly on the uncured composite laminate assembly; co-curing the lightning strike protection material assembly on the uncured composite laminate assembly with heat in an autoclave, and during co-curing, the structural resin and the impregnation resin do not mix and provide a defined resin boundary, and the impregnation resin effectively encapsulates the lightning strike expanding metal foil; and further wherein the cured lightning strike protection composite structure is formed from the co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly, and the cured lightning strike protection composite structure has lightning strike protection functionality, and has increased micro-cracking resistance and degradation resistance. obtaining the cured lightning strike protection composite material structure formed from co-curing of the lightning strike protection material assembly and the uncured composite laminate assembly, and using the lightning strike protection material system to provide the cured lightning strike protection composite material structure with increased microcracking resistance and anti-deterioration properties and lightning strike protection functionality.

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